I mean, yeah, alternate power sets with the main difference being a fundamental mechanics change sounds like a way to get new sets that reuse existing animations and effects to get something sorta new with less effort. Sounds neat and a way to give people who play on theme more options to switch it up.
edit: Not sure you -have- to necessarily set it up as the way it is for Epic ATs, really, just making a new power selection option would probably be easier? Unless you're proposing this for the purposes of being able to have two of a power set for respec/build change purposes which... would be neat but decidedly more effort, I think.