Reactions in general need a rework, especially since one of the main spells that keeps wizards alive, Shield, is a reaction spell that you're supposed to be able to cast when an attack is going to hit you and you can make it miss by casting shield. As it stands now Shield would be basically useless cause you would have to burn a spell slot on casting it beforehand during your turn, then just hope that the enemies actually target the wizard and roll high enough to make Shield feel like it was worth using.