This probably belongs in the unpopular opinion thread but here goes...
A couple of folk have mentioned a game's ability to be able to model having wildly different powered characters, eg. Batman and Superman, on the same team.
I think that Batman and Superman (or Hawkeye and Thor) just don't belong on the same team. At least, not doing the same things. Batman (and Hawkeye) should be doing things like infiltration, gathering evidence to take down evil corporations and corrupt politicians. Superman and Thor fight space gods. I mean, they can theoretically be on the same team, but they shouldn't really be on the same missions. Maybe troupe play is the answer.
This is more about the genre than game systems. I mean, sure, in Champions one can easily spend 500 points on both Thor and Hawkeye and have Hawkeye's arrows doing the same damage as Mjolnir. But it wouldn't be true to the source material.
Of course, the source material often isn't true to the source material so I know I'm on shaky ground here. Like I said, unpopular opinion.