Interesting idea. With my old speedster, I went the 'Reverse Flash' route and had her absorb kinetic energy. As has been pointed out, the powers and origin are less important for RP than just being approachable and likeable as a character. I agree with the don't abuse the fourth wall thing also. Even Deadpool gets obnoxious after a while, lol. Beyond that, do what feels right.
Let me briefly tell you what I'm doing with my character Witchfire, who is also a reaiity hopper. She's a Wiccan who comes from our world and got recruited by her goddess to dimension hop and help alternate realities. Paragon will be her second. She's played COH, but that's only given her a basic understanding of the factions & marquee characters; only a bit morr knowledge than the average person on Primal Earth. When asked about "we're all just a story or game", she replies that imagination is a gateway to seeing other worlds and nobody is any less real. 🙂