The very idea of an 'overpowered' character does my head in. I understand why people want to avoid having players just storming round shooting crazylasers (or whatever the RP's equivalent is), but some people in life are better and stronger than others.

A GM may decide to ask players to be at a set level from the beginning of an RP to prevent crazylasers, but players bitching that a character that is justifiably the strongest beats their character in a fight of some kind really annoys me.

Somebody that has been practicing Kung Fu for twenty years is going to beat a novice. That's the way it is. Those are the characters, and those are their skillsets. Just deal.