It is more managable now, but still very hard. Having more normal poision licens definitely helped, but I think the big thing that needs to change is the toxic oiler's dash. The miniute you are a at certain distance away from them, they charge you, without warning, immediately causing poison and dropping five oil piles. Either remove the dash, or make it more managable, such as fewer/no oil drops upon dash or doesn't cause immediate poison.
The final room is now far too easy compared to the rest of the misson. I can see someone not knowing what the switches do to get burned pretty quickly, but it took me only the first run to figure that out, which makes the final room really easy to control, something the rest of the misson lacks.
And again, my complaint with the lack of story resolution still holds true.
However all, though I like the improvements, keep up the good work!
They do not need to remove the dash. It is balanced, and the oil is avoidable sometimes if you are kiting properly. They also do not need to remove the oil entirely. We do not need to durastically nerf this content, because it is balanced.
The only thing they would do to nerf this content at all would be to remove like one blotch of oil at the end of the Oilgel dash, to possibly help reduce the amount of times it is spawned ontop of you. Basically, as you said, "make it more managable" would be the best route to take IF the devs wanted to nerf this place again (which, I personally think they shouldn't. They need to make this mission harder on the second level altogether).
I cannot agree more with you on the final room being too easy. They definately need to make it more difficult, make the bosses specifically harder.