30% of the spell dealt to you is dealt back to the enemy for 10 seconds. 1 min CD.
Dark Regeneration, a much earlier talent, regenerates 30% HP and increases healing by 25%. 2 min CD.
Unending Resolve, a baseline talent, reduces damage taken by 50% for 12 secs and prevents spell interruption.
Glyphed Healthstone grants 40% HP over 10 secs. 1 min CD, 3 charges, no mana cost.
Come on, at least toggle it up to 50% from 30%, then it is truly a talent worth reckoning.
As for Kil'jaeden's Cunning. A 6 sec grace period to cast spells while moving, while upon activation, removes the passive cast ability? And what good will that do when Warlocks already have Felflame spam, many instant casts, facing requirements, 3 blood fears in combat for use to load up bigger spells?
Why not just make it an entirely passive ability with a 25% (instead of 50%) reduced haste for all spells, and a 20% move speed reduction while casting?