Expertise: I feel required to take this feat because missing sucks. I'm not fond of a feat tax to fix a math error no one wants to own up to. On the flip side disallowing it or making it a freebie to everyone ensures that the hit gap between melee and spellcaster stays firmly in place. If you're a high accuracy class there are more interesting things to take so you're unlikely to have it until at least mid paragon, but then we're back to the same old same old. Blah. Also of note there is a similar feat in the works for weapon and implement split classes in the works for the PHB3 I believe. Suggestion, either completely drop it and its kin, or just give out a +1,+2,+3 heroic/paragon/epic bonus to hit. The ones that need that to hit the most are the ones split between weapons and implements everyone else is pretty much only going to be using their implement group or weapon of choice so you're either making people make a non-choice or punishing those that really need it most.