Of course, a wizard can already do all that, more or less, against "normal" enemies -- which are increasingly rare past first level, for meta-game reasons -- and that wizard isn't too worried about taking a single dart or arrow from a goblin in the shadows.Except that at 5th level, a wizard can kill everything without evasion in a 20-ft radius with fireball, and then take out any three targets with magic missile. Auto-kills. Just casting MM (or MM with metamagic), a 5th level wizard can kill 3 opponents a turn, no save, for six turns a day; a 5th level sorcerer cast 10 of them a day.
Of course, I see little problem in changing auto-hit spells to require a hit (or failed Ref save) and changing half-damage-on-save spells to no-damage-on-save.