I am on Xbox One on a stamina Nightblade. Thaumaturge is NOT working. I have a Stamina Nightblade, and my Killer's Blade hits for 3437 with no buffs on. I took 13 points out of Thaumaturge, and it still hits for 3437. I put 5 points in Mighty just in case ZoS decided to to make Killer's Blade scale of physical damage, and nope it stayed the same but my other numbers went up on Surprise Attack, Steel Tornado, etc... I put another few points in Thaumaturge and it still hits for 3437.
However, my friend tested Thaumaturge on his Sorc and Crystal Frags and it is working. If this is a Nightblade glitch, please look into it and fix it. This is a HUGE hindrance to damage on Nightblades.
Also, my Templar is unaffected by Thaumaturge's damage as well. Get ZoS to notice this, please. This is a huge dps loss to magic nightblades and templars, as well as execute's for stam nightblades.
-Vezuls