reference the DC discussion:

Boosting DC supposedly makes insta-kill casters overpowered and that ruins the fun for melee. The result of this is that saves are so high that only melee and a few people who know how to try harder have fun.

Possible solution:

Have the feats, enhancements and destinies boost all the schools except necro more. i.e. spell focus conjuration could be +2 instead of +1. Or if that is too much SF: conj +1 and GSF: conj +2. The different schools could be set accordingly.

I mean really, what melee doesn't like mobs that are mez'd...?