One of my two major problems with the fighter class is the weapon focus/specialisation feats. In order to keep up with the barbarian in hitting power, you invest feats in becoming a master of one weapon only. It really sucks if you then can't find a magical version of that weapon, or you find a really good magical version of a different weapon - enough to make you wish you'd made a barbarian, really. +4 strength works with anything...
My other major problem with the fighter class is its susceptibility to fear effects - even mundane ones. You'd think a guy who spends all his time eye to eye with monsters would be at least a little bit brave, but noooo.
Perhaps a feat that gives +4 on will saves against fear would be a good houserule.