If the real problem is combat-teleportation, increase the AP cost of Teleport to 4-5 and the cooldown to 4-5 turns.
That's not even that.
It's the "floor is lava" combat mechanics and movement premiums in general.
Because there is no dedicated points for movement, abilities that let you move to an enemy, or an enemy to you are at a massive mechanical value advantage from the get go.
When you add the fact that a lot of the combat is based around surface (ab)use, which the ability to move an enemy also takes advantage of, Teleport becomes the single most powerful ability in the game, even if it did zero damage.
