Went in this time using my standard fire-resistant gear (Volcanic Salamander Mask, Grey Feather Mantle, Grey Owlite Shield). 3 deaths. Between the changes to the toxoilers (that just sounds better to me), polyps spawning, and space, the big rooms were noticeably less chaotic. I was able to avoid the poison for long enough to remedy/heal in most cases.
I liked this version of the boss room much more than the first one. The extra pair and the health boost made them closer to the centerpiece rather than just a quick-knockout at the end.