LoneWolf

Christopher R Taylor is right that incorporating super technology is going to change the nature of the game from a comic book setting to something else.   Add in magic to the equation and you are going to end up with something resembling similar to ShadowRun.  If that is the type of game you want, that is great.  
 
One way to explain why the technology is not able to be mass produced would be that most of the high-tech powers utilize rare components that are not easily obtained or depend on low grade psionic abilities of the inventor.   
 
The other thing that you could do is to have the campaign be a few years into the future.  Given how fast technology advances even a decade in the future could explain a lot of little changes that would allow some advances without majorly altering the world. The technology does exist but is still too expensive to mass produce.  Those way only select organizations have access to the advanced technology.  That would allow something end up something like the normal champions campaign.   
 

Christopher R Taylor is right that incorporating super technology is going to change the nature of the game from a comic book setting to something else.   Add in magic to the equation and you are going to end up with something resembling similar to ShadowRun.  If that is the type of game you want, that is great.  
 
One way to explain why the technology is not able to be mass produced would be that most of the high-tech powers utilize rare components that are not easily obtained or depend on low grade psionic abilities of the inventor.   
 
The other thing that you could do is to have the campaign be a few years into the future.  Given how fast technology advances even a decade in the future could explain a lot of little changes that would allow some advances without majorly altering the world. The technology does exist but is still too expensive to mass produce.  Those way only select organizations have access to the advanced technology.  That would allow something end up something like the normal champions campaign.   
 

I think its best to just ignore the implications and consequences of high tech and superheroes on economics unless its for a specific one-shot scenario.  Why?  Because if you make the world so different and so alien to what we have now, it damages immersion and ease of understanding the world.  The main purpose of superheroes is to engage in power fantasy: here's what I'd do if I had x power/someone ought to do something about this problem.
 
See, Superman's very existence would change society, culture, and science.  He would transform the world.  But the comic books about Superman were about him beating up evil landlords and dictators, stopping mobsters, etc.  Why?  Because nobody put a cape on and jumped from things pretending to fly because they wanted to play out the socioeconomic impact of superbeings.  They wanted to be the guy that beat up the villains, bullies, and criminals.  They wanted to play out what it would be like if someone actually was powerful enough to stop the mafia or corrupt politicians.
 
If you make the world too different from what we now understand and live in, you lose that entire feel.
 
Its fine if you want to do a future-tech, sci fi Champions game, and everyone knows that going in.  But you can't have it both ways.

I have to disagree about the need to create a power for an NPC.  For the most part an NPC should still be written up as completely as can be.  Having what a NPC can and cannot do clearly defined makes the game run smoother.  It is also important if the character is going to be a recurring advisory.  When the NPC’s power radically changes with every encounter it makes the players upset. It also makes things harder when a player tries to counter something when it is not written up.  For example, if a character is hit with an NND with an odd defense having that listed on the character sheet can avoid arguments.  
 
As was pointed out earlier in the thread this is not a power under the control of the character.  This is a rare unwanted side effect of using his shrinking.  It is not something the character should be paying for. 
 

Hugh's post just doubles down on my original question. Normally, the Takes No Stun Power triples the cost of Resistant PD/ED. Will the doppelgangers have full value, or will they be reduced? This is going to be the biggest factor in determining strategy.

The problem with using extra dimensional movement is this is something that negatively affects the character that only occurs or rare occasions under specific circumstances.  Making the characters pay for something that hinders them makes no sense.  You could use the side effect limitation but that gets a lot more complicated.  To do it properly you need to put a limitation on a limitation.  While this is something that can be done it will be confusing.  Using a complication is a clean simple solution. 
 
The special effect is actually extra dimensional movement, but you can use a complication as the game mechanic. 

I would use Accidental Change for this.  Depending on how often he shrinks down to the dangerous size it would be worth about 5-10 point on an 8 or less roll.  The change is that he goes to the other universe.

I ran a magic based game set in the 1920’s.  Even though all the characters were magic based there was enough diversity that the game worked really well.   A lot of the characters were spell casters of some sort but there was also a dragon, a character who was cursed with immortality and a fey who was banished to our world and stuck in the form of a cat.  
 
One of the characters was playing a Dorian Grey type character and was the best Hero and Villain in the game.  He had split himself into good and evil and for the most part kept the evil locked up in a painting.  But occasionally the evil side took over.  He had an accidental change when knocked out.  The most memorable thing he ever did was to summon up a school of Holy Piranha to eat the aquatic ghouls the party had to get past.  
 

There is no reason Accidental Change cannot cause the character to change into a form that is so small it does not exist in our universe.  The only difference between this and shrinking down to 1 inch is size.  Making it fully impairing means the character is out of the game until the character changes back.  
 
The complication has an offsetting advantage that reduces the value of the complication.  While the complication takes the character out of the game for a while it also prevents him from being captured. If this was under the control of the character it would have to be bought instead of being a complication.   As long as the character occasionally has need to shrink down to this size it can still cause problems so is a valid complication.  
 

If you are using the physical limitation you should apply the limitation requires a roll to reduce the value of the complication.  The complication should not be worth as much as one that always affects the character at the same frequency.  As it stands the complication is worth 20 points.  Shrinking is only 6 points so the character can easily purchase 1 extra level that is rarely used.  
 
Accidental Change already takes this into consideration. The value of the accidental change is 5 points for uncommon or 10 points for common.  That seems more appropriate for this.  
 

I would use Accidental Change for this.  Depending on how often he shrinks down to the dangerous size it would be worth about 5-10 point on an 8 or less roll.  The change is that he goes to the other universe.

I would use Accidental Change for this.  Depending on how often he shrinks down to the dangerous size it would be worth about 5-10 point on an 8 or less roll.  The change is that he goes to the other universe.

I ran a magic based game set in the 1920’s.  Even though all the characters were magic based there was enough diversity that the game worked really well.   A lot of the characters were spell casters of some sort but there was also a dragon, a character who was cursed with immortality and a fey who was banished to our world and stuck in the form of a cat.  
 
One of the characters was playing a Dorian Grey type character and was the best Hero and Villain in the game.  He had split himself into good and evil and for the most part kept the evil locked up in a painting.  But occasionally the evil side took over.  He had an accidental change when knocked out.  The most memorable thing he ever did was to summon up a school of Holy Piranha to eat the aquatic ghouls the party had to get past.  
 

I ran a magic based game set in the 1920’s.  Even though all the characters were magic based there was enough diversity that the game worked really well.   A lot of the characters were spell casters of some sort but there was also a dragon, a character who was cursed with immortality and a fey who was banished to our world and stuck in the form of a cat.  
 
One of the characters was playing a Dorian Grey type character and was the best Hero and Villain in the game.  He had split himself into good and evil and for the most part kept the evil locked up in a painting.  But occasionally the evil side took over.  He had an accidental change when knocked out.  The most memorable thing he ever did was to summon up a school of Holy Piranha to eat the aquatic ghouls the party had to get past.  
 

Many Fantasy Hero games do not allow frameworks, so a multipower might not be an option.  If the character has to purchase all the powers individually that will get very expensive. 
 
You only have to purchase the skills you want the other form to have.  I can see a character that becomes an animal losing some of his human skills because he becomes more animal than man.  That actually seems kind of fitting for a Fantasy Hero game.  If the character is actually becoming an animal instead of just assuming an animal shape losing the human skills and gaining those the animal would have seems to be more of how a druid would change shapes. 

You have to throw in Extradimensional Movement as well!
 
 
It's a very unstated rule, humorous in nature.  A few of us used to throw around a joke... once a thread got long enough, someone would suggest Transform or Extradimensional Movement as the "if nothing else works" solution. 

You cannot have darkness that covers the unusual sense group as a whole.  Each unusual sense is considered a completely different sense group.  So, you can have darkness to detect souls (in the unusual sense group), but that does not block another sense in the unusual sense group. You would have to buy each unusual sense as a separate sense.  This does mean when you build your enhanced sense you don’t get any sense groups modifiers for free.  Just build a sense from the ground up to counter this darkness.  It will probably be fairly expensive and if you want to use it to attack you will need at least ranged and targeting and probably sense.  
 
Naked Advantage will not even work. All a Naked Advantage does is allow you to buy an advantage or adder for a power or group of powers.  It does not allow you to create a power you could not create with the normal rules.  If you can build the power with naked advantage, you can build it without it.  
 
 
Something like this would work.  Detect Souls (unusual) Discriminatory, Ranged, Sense, Targeting for 27 Points.

Darkness does not require a way to turn it off.  UAA is what requires a reasonable way to turn it off.  So, the first instance would require some way to avoid the attack, but the second one does not.  The second instance does not have UAA it has Useable simultaneously by 16 people.  That means the targets have to be willing.  The price is also wrong for that one it should be + 1 ½ for 16 people.  The second instance has personal immunity, so I am assuming it was designed as a defense and does not affect the target. 
 
It’s possible the power does have a reasonably common way to avoid it but is just not listed.  When I construct the power in Hero Designer it does not list the defense for the UAA, the comment section is commonly used for this, but nothing prompts you for it.
 
The power is fairly strong but there are plenty of ways to get around it.  As Grailknight pointed out combat sense will negate this. 

Darkness does not require a way to turn it off.  UAA is what requires a reasonable way to turn it off.  So, the first instance would require some way to avoid the attack, but the second one does not.  The second instance does not have UAA it has Useable simultaneously by 16 people.  That means the targets have to be willing.  The price is also wrong for that one it should be + 1 ½ for 16 people.  The second instance has personal immunity, so I am assuming it was designed as a defense and does not affect the target. 
 
It’s possible the power does have a reasonably common way to avoid it but is just not listed.  When I construct the power in Hero Designer it does not list the defense for the UAA, the comment section is commonly used for this, but nothing prompts you for it.
 
The power is fairly strong but there are plenty of ways to get around it.  As Grailknight pointed out combat sense will negate this. 

You cannot have darkness that covers the unusual sense group as a whole.  Each unusual sense is considered a completely different sense group.  So, you can have darkness to detect souls (in the unusual sense group), but that does not block another sense in the unusual sense group. You would have to buy each unusual sense as a separate sense.  This does mean when you build your enhanced sense you don’t get any sense groups modifiers for free.  Just build a sense from the ground up to counter this darkness.  It will probably be fairly expensive and if you want to use it to attack you will need at least ranged and targeting and probably sense.  
 
Naked Advantage will not even work. All a Naked Advantage does is allow you to buy an advantage or adder for a power or group of powers.  It does not allow you to create a power you could not create with the normal rules.  If you can build the power with naked advantage, you can build it without it.  
 
 
Something like this would work.  Detect Souls (unusual) Discriminatory, Ranged, Sense, Targeting for 27 Points.

You cannot have darkness that covers the unusual sense group as a whole.  Each unusual sense is considered a completely different sense group.  So, you can have darkness to detect souls (in the unusual sense group), but that does not block another sense in the unusual sense group. You would have to buy each unusual sense as a separate sense.  This does mean when you build your enhanced sense you don’t get any sense groups modifiers for free.  Just build a sense from the ground up to counter this darkness.  It will probably be fairly expensive and if you want to use it to attack you will need at least ranged and targeting and probably sense.  
 
Naked Advantage will not even work. All a Naked Advantage does is allow you to buy an advantage or adder for a power or group of powers.  It does not allow you to create a power you could not create with the normal rules.  If you can build the power with naked advantage, you can build it without it.  
 
 
Something like this would work.  Detect Souls (unusual) Discriminatory, Ranged, Sense, Targeting for 27 Points.

You cannot have darkness that covers the unusual sense group as a whole.  Each unusual sense is considered a completely different sense group.  So, you can have darkness to detect souls (in the unusual sense group), but that does not block another sense in the unusual sense group. You would have to buy each unusual sense as a separate sense.  This does mean when you build your enhanced sense you don’t get any sense groups modifiers for free.  Just build a sense from the ground up to counter this darkness.  It will probably be fairly expensive and if you want to use it to attack you will need at least ranged and targeting and probably sense.  
 
Naked Advantage will not even work. All a Naked Advantage does is allow you to buy an advantage or adder for a power or group of powers.  It does not allow you to create a power you could not create with the normal rules.  If you can build the power with naked advantage, you can build it without it.  
 
 
Something like this would work.  Detect Souls (unusual) Discriminatory, Ranged, Sense, Targeting for 27 Points.

Not everything needs to be explicitly defined in the rules.  Even in a survival focused campaign you don’t need to explicitly define every single detail.  For a cold environment you can define the attack as an NND with the defense and list winter clothing as one of the defenses.   There are a lot of things in the game that do not have power based builds, but are still used.  Food and water are going to be even more important in a survival-based scenario than clothing, but I have never seen a write up for ordinary food and water.  
 
My advice is to focus on the attack portion of the survival challenges instead of the defense.  Write up the cold attack and leave it at that. 
 

Not everything needs to be explicitly defined in the rules.  Even in a survival focused campaign you don’t need to explicitly define every single detail.  For a cold environment you can define the attack as an NND with the defense and list winter clothing as one of the defenses.   There are a lot of things in the game that do not have power based builds, but are still used.  Food and water are going to be even more important in a survival-based scenario than clothing, but I have never seen a write up for ordinary food and water.  
 
My advice is to focus on the attack portion of the survival challenges instead of the defense.  Write up the cold attack and leave it at that. 
 

The way it is described in the OP would be a multiple attack, but it could be bought as a combined attack.  If you bought a 1d6 RKA and linked a second 1d6 RKA to the first, that would be a combined attack. You could not use the +5-point doubling rule for this and would need to buy the second RKA at full cost.  
 
What that would mean is that if you hit you roll the damage for each attack and the targets defenses would be applied fully to each attack.   
The thing to keep in mind is that with the Hero System there is usually more than one way to build any power.  Some ways of building them are more efficient so those are usually used, but that does not mean they are the only way.  I would not recommend purchasing the above power even though it is a legal power.  A better way to build the above power would be to buy a 2d6 RKA with the limitation reduced penetration.
 
Buying it as a 1d6 RKA and using the +5 to get an extra attack would allow you to use the two weapon fighting rules, but those modify your combat values.  Normally using multiple attack is a full round action that reduces your DCV to half and takes a -2 OCV for each attack past the first one on all attacks.  There are skills that can alter some of these, but they cost points.  Two weapon fighting using multiple attack rules are more common in heroic games than in champions games.  If a Champions character wants to use two weapons, they often build the attack that way from the beginning.