I was already sceptically when they introduced this, letting a pure class, that was always DPS the ability to tank. Warlocks aren't strangers to tanking from normal dungeons to Illidan demon form with Leotheras and Kael Belf mage on the mix, but despise all this, the glyph and direction seemed strange because they separated the feral tree on druids for the sake of balance, so introducing it to warlocks felt weird.
Nevertheless after the shock and awe at very start of beta were DA was actually very OP, this gave alot of ppl false hopes. GC said that this would be just for funsies and small utility, warlocks would never tank, countless nerfs were made to both survivability and damage making it kinda whats the point of it, the real fatality to some warlock dreams to main tank was perhaps the removal of pve crit imunity and introduction of new vengeance mechanics to the "real" tank specs
Now this is on live and I wonder the hell were they thinking? Any spec with Supremacy Voidlord tanks better than DA itself. The survability its better, its easier to heal pets than heal ourselfs, DA threat and damage is rubish and not even a real taunt was given. Dont confuse what I just said with Voidlord is too good, nerf it. Iam very glad that FINALY they gave us a real tanky pet, its the fact that DA its rubbish
There are some delusional warlocks and rerolers out there still, but sorry to be blunt, Warlocks wont MT/OT in MOP in any half-serious raid group. Given the fact that aggro will be hard to hold with inexistent TPS and real tank classes can probably double the damage of a DA warlock because of vengeance and that will mater in MOP tight enrages Some ppl are tanking normal DS and thats fine, but DS is no benchmark anymore 35% nerf and healers with almost infinite mana regen.
You may accuse me of anti-tank movment, and your right because I know that if they made Demo a true main tank and if they focused on that it would probably come at the cost of DPSing as demon. The option would have to pass by a 4th spec but thats out of the scope for this expansion now.
Not much stuff they can do to make DA salvageable now. Perhaps increasing damage in it its one of them, giving the crit imunity its other. Even with this we wouldn't become Main tanks because of vengeance and no active mitigation(Fury ward its not enough)
DA is a good idea on paper but failed, bad foresight and bad design, Blizzard are always adamantly saying that if they do X they cant do Y, well they did DA, I have no idea what Y could be but I believe that Y could had been something better than DA.