Its not really a warlock fight any more then any other dps fight is a warlock fight. The only thing that makes it special is enslaving the pit lord which is really there just to tank and heal us. Line of Sighting and keeping up aggro debuffs isn't really that fun of a fight. There could have been so many different ways of handling the encounter.
Instead of the a dps check with gimmicks to avoid threat or potions to remove the "soft enrage". They could have made it more like a platformer and required us to do certain tasks. Enslave demons, use eye of kilrogg somehow, fear, banish, use gateways to get to different platforms. Have all of our demons help us like a hunters stampede.