Re: Super Origins
I don't limit any origins. I don't see the point. Usually, if I'm running a superhero game, I'm trying to run something that emulates the source material. Is it unrealistic for radiation to grant superpowers? Sure, but several of Marvel's iconic characters received powers in just that way. Can aliens do odd things to a game? Yes, but the iconic superhero ever is an alien. Is ultrahigh tech really going to hurt the game? No, not really. I don't see the problem with a character who happens to be a billionaire inventor/industrialist who also uses technology he doesn't share to help him fight crime.
Anyway, unlike a monthly comic in Marvel or DC, I'm not obligated to maintain a static setting - so someone with the capability to produce extremely high technology who actually does so for his or her own benefit isn't really a bad thing, to a point.
I have run a game in the past that limited origins, but that's because the setting itself had a limited set of origins to work from, not because I disliked the origins I chose to exclude.
As for playing in games, if a GM crumpled up my character sheet and threw it at me because he had an irrational dislike for the keyword/excuse I used for my superpowers, I'd find someone a bit less intolerant and tyrannical to game with. If he said up front that he doesn't like certain origins, then it'd depend on what the origins were and his reasons for excluding them. "Wanting to maintain a tech level equivalent to the real world" is a pretty good reason for not having characters like Iron Man or the Engineer. Hating it because it's unrealistic just strikes me as really odd.
Now I'm going to go write up an alien mutant billionaire industrialist with magical nanite armor.