Played with the buffed Hellforge Host at a spearhead event last week, here are some thoughts.
I played three rounds, two against ork big mob and one against skaven gnawfeast. I noticed my opponent's going for the tormentor bombard over the dominator engine now that it has reinforcements. In the future I will focus on screening the bombard over the dominator. I was afraid to commit my dominator engine and I think that hurt me, my opponents didn't even try to destroy it like they have in the past probably because of the reinforcements. I had a much easier time against the skaven, I was able to use my cohort as an anvil and the dominator as a hammer. The war despot's new ability was far more usefu then the original and saved a few of my cohorts and got the dominator engine cooking from turn one. Depending on your turn order and opponent getting your slow guys onto objectives may prove difficult so try to play your battle tactic cards as aggressively as possible. Don't hesitate to put DPP on your cohort especially after they've been reinforced, surviving a combat and holding a point can be a lot more valuable than an extra attack with the dominator engine.
I'd love to hear from anybody else who's played it.