or adjust "hide" for thf.
recast 1 min, well either it removes 50% enmity of the thf who uses it or give an piece that augments "hide" and gives the "removes 50% enmity"-function.
another way could be a neckpiece as example which could like this:
str+5 dex+ agi+5 (allround necklace ^^)
"augments trick attack"

"augments trick attack" means: 25% of your actual enmity is added (and removed from the thf) to the enmity natural created on tank (or w/e) by using trick attack.

well both ways could help to fix the enmity issue at least on thf.