Re: World War Two Campaign
Well, you said "the Golden Age superheroes", so I assume you mean a campaign where the players actually use the classics.
In which case, I think it boils down to whether or not you want to heroes to be active on the war front or not. The difference between an All-Star Squadron or Invaders-like game. In other words, whether the players protect the home countries from invasion and spies, or whether they engage in sabotage or direct attacks on Axis forces, or possibly both. Power levels become pretty important in that case, and the GM'll need to know what kind of game he or she wants to run first.