Relique du Madde
Adventurer
I was actually thinking 4th edition would be a great system to use for superhero type games, I would suggest including a card if your using them reminding players that they don't only have to use their prescribed powers.
It would be... but it would suffer because you can't customize your powers or make some insane power chains like you could if you used Mutants and Masterminds.
Now maybe if you could speed up combat it would be perfect, decrease villain hit points increase damage maybe.
Just toss out randomized damage and use M&M's damage saves. Problem is that Strength for Toughness would make Strength too important of a an attribute since many characters would have Strength Based toughness.