Well,there's the neutered Power Critical in Complete Warrior. It now gives you a +4 to confirm a crit threat. If all 11 levels are fighter, you might consider Greater Weapon Specialization. +4 to dmg in general sounds good (twice that on a crit). If you don't have it already, power attack wound be a good choice.
There's two feats critical related in the BoED. The first is resounding blow (on a crit, save or foe is stunned or dazed or something for a round; save = 10 + half level + Cha...I think). Another is an exalted feat called Quell the Profane. It does 1d4+1 temporary strength damage to evil foes.