I think the environmental damage is a positive during the battles, I dont think certain ones should linger around after a fight sequence though. Fire that has been cast on the ground should go out after a certain amount of time.
Also I have walked over acid puddles without seeing it. I would like it if the colour was a little more obvious for acid as i could barely see it on a stone floor outdoors.
When the whole party is walking outside of a battle they should have the sense to walk around environmental surfaces automaticlly. Or not move at all if you're required to jump.