Immune to criticals are easy. Penetrating Strike [Dungeonscape] gives up Trap Sense (useless anyways) and gives you ability to deal ½ SA damage to normally immune creatures while flanking them.

Combine this with Darkstalker [Lords of Madness] and you can flank just about anything (this stops All-Around Vision and similars from intervening with your flanking in addition to being awesome with Hide; negates Blindsense, Blindsight et al.).


The only problem are amorphous creatures...can't think of anything to help there.