Sure, each character has it's own flaws and advantages, just sometimes that advantage might be too big, overpowered. Starcraft 2 is a good example indeed, now imagine a unit, that no other unit can effectively deal with, i would call that imbalance. That you can't counter it! Well such things already exist in fonline:2238, like the hot topic about crit bursters, you can't counter a 330 damage burst in your face, game mechanics, features doesn't allow to do that. So the only way how to counter that, is to make a similar build and smack back with 330 bursts in face. Some sort of balance exists even then, but it's a lot narrow than before.