Teleport is not overpowered. It already has a high cost and the damage reflects this. The truth is you need a skill like Teleport in this game, to let the player really utilize the terrain effects, tactics etc. to their own imagination. Nerfing Teleport is like nerfing fun.
Today I learned one AP is a high cost. The damage of the ability is comparable to single target damage abilities but teleport also has extreme utility and can also be used as an aoe. This isn't even factoring its short 3 turn cooldown in comparison to the longer cooldowns on many of the other abilities which don't even begin to hold a candle to the impact teleport brings to a fight. It stops being tactical when the move is an obvious go to in any situation. The move is so strong that the teleport gloves are still on my characters in combat at level 8. You're fun diminishes my fun, leaving teleport the way it is makes too many things in this game trivial.