I think I speak for the majority of all warlocks when I say this. Blizzard.
Would you please be so kind and remove Demonic Servitude as a talent..
With the removal of Dark soul in legion Warlocks have 1 dmg cd, and not very good one either.
Summon Doomguard, a temporary pet that we are unable to control, meaning a cooldown we have no control over when killing priority adds.
Demonic Servitude removes this so called "cooldown" and makes grimoire of sacrifice a dead talent aswell.
Not only that but it is also a really boring lvl 100 talent.
It does nothing but removing the other demons we have.
Blizzard said it them selves, they want to make the demons feel unique to each spec:
Imp for destruction, Felhunter for affliction and Felguard for Demonology.