Re: Ringers (prompted by the Black Widow thread on Dark Champions)
In terms of powers, I neither encourage nor discourage the thing. Since, to be honest I don't think the bulk of superhero write-ups or comics characters could be discribed as "innovative". Nothing is new under the sun. However, generally I expect my players to come up with interesting characters STORY-wise. As long as they do that, I don't care if it's a bat-totem shaman, Superman under the name "Strontium", or some "totally original concept". Of course, YMMV depending on the nature of the player in question.
While I would say that 50% of my (N)PCs in my campaigns are "original", 25% "inspired by" and 25% "dead ringers" -- I have two personal examples of "ringer-ness":
a) Recently I made a character for a medium-level "mystic"/weak-horror campaign. The GM allowed me to create two. The first I created was a werewolf like character whose powers are not all that unconventional or specially-interesting. But a fun character nontheless in practice. However, the second is a dead-ringer named "Jake Scheuller" aka "The Cricket" based on Jack Burton from BTILC. He's got his own "original" backstory and associates, and his personality is similar but not exact ( just select juicy character traits from Russell's portrayal.). He's even got his "Trusty" Mac-10. However, he has as many luck-based powers packed in as I could balance. He's not a normal like the "real" Jack Burton (who was really just a bumbling side-kick), nor does he have that "typical all-around game balance" of most champs characters. He's a huge risk, I know he could die at a moments notice, but that's ok, his luck powers shake things up, create hilarious unexpected RP and combat scenes. I have several more powers to go before I consider him complete, but I'm having a blast playing him. However, he's not a primary PC (maybe that's the part of the charm, I dunno).
Not a character, and not a dead-ringer, but when my friend (who also GMs HGS ) first saw Terminator, we were so jazzed about it, that we decided as we walked out of the theatre that we'd each GM a Terminator-inspired module. Now, we were playing an Espionage-genre campaign at the time, so the prospect of meeting a Terminator is particularly terrifying on one level, especially in that kind of genre. His module was pretty much a straight port of the movie, including time-travel, but with things repurposed and mixed up a bit. Not particularly bad, but not that outstanding either from our normal fare. However, for my module, I decided that I loved the fact that the Terminator was technologically advanced, but I disliked the time-travel aspect (for purposes of GMing a module) and needed to totally revamp the plot/premise so that it would work for the PC's / scenario of the campaign. So I cheated a little, I mixed Terminator with Blade Runner, and decided that the "Ersatz" (aka Replicants) were a product of a super-secret society of scientists that started after WWII, who created a uptopian society/organization that benefitted from the best minds of the world working in secret without politicial hinderence. The Ersatz were foes, but they were well intentioned foes. The scientists had their own form of government and a goal of forced-participation in a world-utopia. "Skynet" was a super-AI designed by the scientists to be an impartial slave-judge to guard against the intitial uptopian ideals being corrupted over centuries/etc. However, this AI secretly broke free and had his own sub-goals (the freedom/equality of the Ersatz). It worked out so well, that not only did it inspire a slew of modules and over-arching plots for my own campaign, my friend "stole" it for his own in his games.
I would say in my experience that the concept of creating "dead-ringers" has the potential for being HIGHLY important to a long-term running game, if it is done for the purpose of "a new take on" versus just trying to copy something. Start with an exact copy (1.0), through in something totally unrelated (2.0), and then "refactor" it (3.0). Just judiciously, that final form has never failed me in the games I've played.