People like me who love role playing wizards have had the ability to customize their wizards to their specifications severely limited. This is because a large number of character builds were dependent on a mechanic that has been removed from Skyrim. That mechanic is spell creation. Because it is an 100% optional feature (and thus has no impact on others), there is no legitimate argument to be made for its removal. Therefore, I would hope Bethesda understands this and reintroduces a spell creation system in future DLC or TES games.