One spell I truly consider overrated off the top of my head: Disintegrate. Does nothing on a successful save and the damage isn't any better than a good Fighter or Paladin nova when the enemy does fail the save.
I agree with this mostly if looking at Disintegrate strictly as an offensive spell. But it does have some utility purposes - destroying a wall of force can be vital at upper levels. Just disintegrating an object, a door, a hole in the boat, etc has its uses. The only time I would ever use it offensively if the target had disadvantages on dex saves (caught in a web or restrained somehow).