Something just struck me that might be pretty cool. Instead of making those touch spells negate enemy attacks, how about making it so that they actually reflect enemy spells instead?
At the moment, while those touch spells are ok defensively and can be used occasionally, it is still usually preferable and easier just to dodge out of the way of enemy projectiles. If you were to make it so that enemy projectiles were reflected instead, not only would it be cool and make the player feel more like a badass ninja, it would also give the player a lot more incentive to use them defensively rather than simply just dodging. Seems like a nice way to freshen up touch spells while also introducing a new cool mechanic. Not sure how feasible such a change is, though.