Would love for someone to weigh in on this, just had an epic conversation with my DM about what the point of your key mod is as a caster if all abilities seem to either auto hit or use a touch roll (dex). Only things he could point to were saves against spells and a few spells which increase dmg/heal based on your key mod. Seems a little off to me but I am new to this game. Its like asking a barb to make a int based attack roll to see if he was smart enough to swing his sword and hit something...
