Actually, yes. I dislike it when one character is too powerful, as it takes the shine away from others.
If it's me playing a character I think hard about retiring it or changing it. There are problems though - D20 as it is, certain classes will suck at various or all levels. Fighters are problematic at high levels without a lot of magical gear and wizards are problematic at low levels without meat shields.
So, taking that in mind - as I 97% of the time GM anyway - I always try to have an encounter that lets each character shine. For instance -
Say we have a party of B, a Soldier/Pirate known as the most dangerous swordsman in the land, L, a Soldier/Borderer with a few more statistics in the mental statistics, and C a Soldier/Nomad with a checkered past. Well, more checkered than most. B, due to attribution of feats and statistics and assuming a fair fight is had will hands down most likely be able to kill L or C, or both together. Luckily, neither L or C like fair fights. But how do I avoid having B shine whenever combat is abroad? Story reasons. Sometimes B fighting wouldn't achieve anything, and L fighting would. Or some such.
For B, while head of a kingdom, only did it for the prestige and vengeance for various reasons. He doesn't much care for actually ruling. I organise for him duels, arenas, NPC's insulting him and the various claimants for his reputation. It leads into a number of stories that he is then interested in. He's only interested in enough silver to keep him alive and fighting. There's probably a sad end in front of him, killed by a younger man in the middle of nowhere for no purpose.
L likes being a general, after finding his true love. While a dangerous opponent (His reputation of iron grip is Beowulf worthy) I organise a number of rebellious factions he can unite, armies led by people he doesn't (Or does) like, and so on. B fighting his battles for him would be slaughter, but wouldn't achieve anything.
C likes riding the open plains, drifting until he finds what he's really looking for after killing the slave master that owned him. He finds civilised life boring and slows his reflexes - and he's no good at anything that doesn't involve killing anyway. He doesn't know what he looks for, but he tries to find it everywhere.
For C I organise a lot of exploration of ancient places, some mounted combat, promising women, promises of power and luxury never quite gained.
I never directly inhibit the power of the characters - I only make it so that each one shines at his chosen speciality. That way, munchkined power isn't so important.
