The key to remember is that characters are not balanced in character generation. They're balanced in game play.
As mentioned above, you have limits on what you can add to your dice pool:
One die per power set.
One specialty.
You can of course use PPs...and that's where the second balancing act comes in.
If you're rolling mostly high dice like d10s and d12s, you're not going to be rolling as many opportunities as say, Black Panther and his wall of d8s. This means you're not getting as many plot points. This means that you're not getting to spend as many PPs on adding a third die to your result, or adding a second effect die, or being able to actually use your Invulnerability SFX.
So if you're playing Thor or Hulk or the Thing, you'll be depending a lot more on using your Distinctions for d4+PP, or activating your own limits, something that 'weaker' characters don't have to do as much.
