Yeah I'm thinking people are exaggerating how powerful teleport is.
If you ALWAYS take teleport on every playthrough you do, then how do you know it's overpowered? How can you tell that it's teleport giving you the victories, and not just the fact that classic mode is pretty easy? I have played without using teleport after level 4, when I switched out the teleport gloves on my mage, and it was still pretty easy to cheese a lot of situations (mostly with slows from oil and a bunch of knockdowns).
I generally don't have teleport on more than one person in any playthrough; I'm not a huge fan of Aerothurge and the -1 lucky charm on the gloves irrationally bothers me even when I never use the person wearing it to open chests.
It is certainly easier with teleport, I'll give you that, but I think a simple increase to 2 ap or having armor/magic resist block it, or replacing it with something that can only be activated on allies for the early game would be more than enough for it.
