Re: Villain: makes hero's powers go out-of-control
Very interesting idea. Reminds me of "wild magic" in AD&D...
Sometimes the rules are a too cumbersome to fit your idea's into, sometimes it's better to not get hung up on powers, points, and advantages/disads.
I'm thinking when the player use their powers (including superhuman strength) have them make an Ego roll modified by the active points in the power or stat / 10 (maybe 5 if you feel like punishing them). If they fail then something bizarre happens; the power goes haywire, the power does something unpredictable. Maybe make up a quick couple of tables with strange effects on them, have the player roll to see what happens...or pick (or make up) one yourself to heighten the drama. Story first, rules second...know what I mean?
I think that it's not within the rules but it would probably work ok.