Tactically, this is fine. It makes surfaces more deadly, and forces you to think. I like it.
I disagree with that. In reality it removes an option. When an opponent ignites or poisons an area around (and including) your character there's a few options available. Running out of the impacted area should be one of those options, but instead it's the worst move you can make because it inflicts the most damage. Standing perfectly still inside the impacted area is actually a more desirable option, which tactically makes no sense.
This is not just a problem that impacts players. It also makes elemental surfaces far too useful against monsters. Setting an area ablaze around a monster will do far more damage than it should if the monster attempts to leave the area of effect.
