The Monk transmutes are bad. Really, really bad. Like, I would never use them over Valhalla bad. + to damage is super weak (3 and 5), stunning fist needs to be expanded more (it's REALLY difficult to get 19 and 20s be sliding two pucks, if players are doing it correctly). Relic should be 19-20, Legendary should be at least 18-20, maybe even 17-20. Cap it at once per room per monster if you're worried about repeatedly stunning the monsters. The additional psychic power is cool, but way too situational. Auto-kills are useless and not very fun. So, suggestions:
Expanded stun range (1/monster/room): 19-20 (relic), 17-20 (legendary)
Something else besides raw damage
something else besides auto-kill
something else beyond additional psychic, maybe +1 power and +will saves, or auto succeed on a failed save 1/game.
I don't have any good ideas, but I'm hoping others do.