I actually rather enjoy all the environmental damage and the changes that can happen when you mix environmental effects. But yes, the way the characters behave makes it very vexing.
Revealed traps and visible environmental effects should be effectively inaccessible areas for the AI unless they are already in them, or you FORCE them in to them. The idiocy of them just gaily traipsing through the searing flames is maddening. NO ONE DOES THAT. No one that lived past the age of 5 anyway.
Having them flee the damage zone though is contentious. They could easily just run into worse danger. Knocking you into turn based mode whenever a character gets caught in an environmental mess is probably good. Then you can decide what to do about it rather than realizing after they are dead that it even happened. This would only be if someone broke open a barrel or some such that got them caught in an effect, because they should never have just strolled into it of their own accord in the first place.
There are *certainly* issues about how the party follows the crown, but they would be mitigated in large just by having the AI avoid playing puddle splash in the OBVIOUS POOL OF ACID as they run laps around the new leader you just clicked.
