For me the problem is not the teleport on the gloves. It is the teleport spell from Aerotheurge and the fact that any char in a group can possibly have it. Using the gloves gives you disadvantages in stats which grow bigger and bigger with increasing levels. They also look quite ugly on elves.
The spell needs a memory slot and one attribute point, but otherwise?
Changing the range of teleport would be near impossible with the current game design. The damage could be changed for sure. Having it blocked by armor would make the Fortify spell, beloved by the AI, more or less meaningless. I would just restrict the teleport ability to one a group, maybe with some possibilities to increase the numbers coupled with disadavantages.
