This would be interesting, since the doomguard originally had rain of fire(back in the days when you had to enslave the thing). What abilities would a perma doomgaurd/terrorguard have? Would they still have cripple and dispel magic?
That then begs to ask what would an infernal have? They never really had any abilities, they just had a PBAoE passive with a decent amount of health, armor and some heavy elemental resistance. I would love to see the infernals get something akin to meta's MF buffed immolate aura on a cooldown, and maybe a point blank aoe stun? Pretty much with the intent of making them extremely effective at handling those short life adds, but still keeping the passive aoe damage aura to still give a bit of cleave, in turn making it sort of life a super powered fel/wrath guard, but without as serious single target damage, thus letting the fel/wrath guard keep their niche and still not tossing the doomguard out of the competition.
All of that being said, I still want a pit lord, maybe not as an ability, but at some point in the tiers for WoD, I want to enslave another Pit Lord. Like vanilla ZG and the imps there.