GURPS Fourth Edition lets roleplayers create any character they can imagine, from any time or place. They can be customized with hundreds of advantages, disadvantages, and skills, not to mention magic spells, psionic powers, martial arts moves, superpowers, and equipment from pitchforks to starships.
And yes . . . it can all get a little complicated. If only there was some sort of super-smart machine that could remember all the rules for creating characters, recall them instantly, memorize characters after you made them without ever forgetting, do all the math without making a mistake . . . but that would take some kind of computer or something . . .