For me all damage over time attacks will benefit if enemies would be slower. You hit them at the distance and hide, while waiting when it take its toll.
Only change I would apply to acid attack would be that at some point if there is enough acid accumulated on single body part it makes 20 damage per turn instead of 10.
It could work in the missions where your goal is to exterminate all opposition. In defend haven and scanvenging missions - not so much.
That is why you wouldn’t use Damage Over Time attacks all the time. 
I am also wondering whe dev’s don’t give us a goo weapon (like a goo grenade similar to the goo blast from goo Chiron). Maybe they save it for DLC? Or maybe they did some testing and consider this option overpowered?
Well goo is specific pandoravirus mutation. It would be strange if it would be us who use it. And we have fire to block routes.
I’d like a goo weapon, but Pandorans are probably immune to it. After all, most of them can jump 1 floor like our agile legs mutation (which is immune to goo).