Darned if you do, darned if you don't.
I've always looked at it like this:
Having a higher OCV means that you have a better chance of hitting the person at all. The damage dice actually determines how well you hit.
I've played another game system (That I should say was no where near as good as the Hero System) where the attack dice determined how well you hit and you did not roll Damage Dice. The game felt flat. All depended on that single roll (actually the defender got to roll to see how well he took the damage too). And with a variance of 1 to 20, you could do well and knockout your opponent in a single blow, or pound on each other all day. When the big baddie that we were fighting fell down-went-boom with the first punch, we were all disappointed.
Champions seems to be balanced well with the damage dice. You can roll well, but you seldom roll very well, and the inverse is also true. This tends to lead to generally rolling pretty average. This puts the emphasis is on the abilities of the character and not the luck of a die roll.
But what do I know? I'm Incompetent. 8-)
I hope that you find what you are looking for,
LegionX