It depends on what setup you are looking for. Enfeebling, Nuking, Idle, Resting or Magic Accuracy. There is no 1 set of gear that covers every situation. The closest thing to that would be full Morrigan's set but even that is lacking in certain areas. But to answer your question, for full nuking Magic Attack Bonus gear > Int > Elemental Skill gear > Magic Accuracy gear in that order of importance. For enfeebling setup Enfeebling Skill gear > Int or Mnd gear depending on what spell in that order. Magic Accuracy gear Elemental Magic skill gear > Magic Acc > Int again in that order. Idle gear(when you are not casting or resting) Refresh > Magic Def. Bonus gear. And finally resting gear HMP gear(mp recovered while healing) and refresh gear. Hope this helps!
for End game u'll find that Elemental magic skill gear and or Magic acc gear is far better than MAB. some mobs dont die in just a few nukes.