Damage taken does not do anything to emnity atm (In XI damage taken REDUCED emnity).
Healing is 1 heal = 1 threat, ethers are on 5 minute CD's, and Sacrifices HoT causes 0 threat.
Oh that -Emnity ability from CNJ only works on CNJ spells and has zero effect on THM ones.
But in regards to threat... you cannot reduce MP costs AND reduces threat costs... that will bring us back to pre-1.18 where healers could spam endlessly... reducing both = no thanks.
You can either:
Raise MP cost, reduce threat amount.
or
Reduce MP cost, raise threat amount.
If any change was to occur regarding those 2 elements I would say it would have to be either of those (or stay the same) or healers will once again require zero skill to play.
Btw having everyone with accomplice helps leaps and bounds since its very hard for meele to catch a tank's threat right now... they accomplice the healers / everyone wins.