Well an abjurer could take spell focus (enchantment). I don't really see the problem. I agree with the spelll selection thing, but I think that it's one of the key element that makes it all balanced.
The point in making a specialist wizard is having him more, well, sepcialized you can't expect of a specialist to be able to face every situation the same way a non-specialist wizard will. You have to accept that in some situation you'll be less effective than another wizard. That's the price you pay for being able to cast one extra spell per spell level per day.
The point in making a specialist wizard is having him more, well, sepcialized you can't expect of a specialist to be able to face every situation the same way a non-specialist wizard will. You have to accept that in some situation you'll be less effective than another wizard. That's the price you pay for being able to cast one extra spell per spell level per day.