I don't know if anyone mentioned it but there is an ally-only teleport skill in DOS1 called 'featherfall' which would solve the OPs issues. You wouldn't have to nerf anything just implement featherfall early game, like on teleport gloves. Could solve Gawin quest and get chests.
Then implement the enemy teleport ability at higher level, when it would be more appropriate to have powerful ability. In DOS1 you could teleport enemies at level 1 that is OP.
also a very good point