As it stands I rarely use staffs because they don't improve your stats, they're a pain to recharge and generally my spells are more powerful anyway. So maybe this mod already exists, but I think this feature should be in the game. Staffs which allow you to cast the currently equipped spell through it, whatever that spell may be. So the staffs themselves actually don't do anything, it's just an extension of the hand. However they could be enchantable, and allow the same enchants as rings or necklaces, allowing you to increase your magika or whatever. Or you could enchant them to give you a spell effect multiplier. What do you guys think?
