There are two significant reason why Teleport is broken.
1) Enemy pathing is terrible
and
2) The enemies don't know how to use their own teleports.
-Seriously the CPU really has to stop using "Phoenix Dive" as an attack.

That is it honestly. Anyone who argues it "does too much damage" I must go "REALLY?" because it is probably the least damaging spell (of ones that do damage) in the game.

The only nerf I'd even suggest for teleport is perhaps it should have a higher memory cost to represent how useful it is, in combat.