If we ask the question, "is balance good," the answer is, in my opinion, it depends what you sacrifice to achieve balance. Imo it is fine to have a slightly out of balanced system, provided it makes for more enjoyable gameplay. Obviously, fun is subjective, so that comes down to player preference, but there are some things which surfaces very clearly do add to the gameplay. For example.
• Opportunity cost of deciding whether you want to remove the surface or leave it there.
• Restricting movement.
• Adding interesting elemental interactions (the whole cloud thing div 2 had).
• Rewarding clever gameplay (being creative with the surfaces).
It also obviously has the following downsides.
• When its always easier to apply a surface than it is to remove it, the opportunity cost is pretty much gone because the best solution is always, "live with it." To avoid this, the relative ease of applying a surface needs to match the ease of removing it (for example, a free action "douse" which would put out a flame on the character and a small space surrounding them would be roughly equal to the ease of the cantrip).
• It messes with balance.
I am a fan of surfaces because of those first 4 points there and I can live with the 2nd negative, the 1st negative is the one which is imo more important because it counters the 4 points that I mentioned above. This was a problem in DOS 2 because of Necrofire (an ooze just needed to move around to apply it, but it took 2 spells to remove it).
So implicit in what you're saying in the first line here is the idea that balance entails a sacrifice by necessity, which is a mistake. I'll leave the counter-example to your imagination so we don't get bogged down in another series of misunderstandings. Sometimes I forget that not everyone has exposure to syllogistic logic.
The rest of it is you arguing against a strawman or going on tangents that don't directly pertain to what I said. I get the sense that you're trying to prove this isn't a particular type of PVP game for some reason. I'm not sure if you have an annoying friend IRL who keeps treating it that way, but whether or not it's a PvP game, or a certain type of PVP game is not really relevant to anything I said. Any number of the interventions you describe as uniquely environmental could just as easily be managed by another player without changing the nature of the game or the intended goals of the systems in it (i.e. enabling or preventing the player from beating the campaign.) It doesn't matter except in terms of the player's motivation whether 20 goblins are controlled by an AI or by a human being, I think your arguments here are more emblematic of your own competitive nature than anything to do with formalizing categories with design utility.
But there are some interesting things here: I think your points about the economy of surfaces are really interesting, thinking about how many actions it takes to remove them and the balance considerations that arise during spell selection vis-a-vis the number and type of surfaces that exist organically in the game. I.E. it will emerge that firebolt is better than acid splash if there are X combustible objects in the first Y hours of the game. Hopefully this is something that Larian is thinking about. Also considering that it may also slow the pace of combat by lowering the DPT of characters who focus on removing surfaces, or martial classes that have to maneuver around them to position for optimal damage output. How do you think these interventions might affect fights later in the game? While fire's damage may not scale, your fighter going suddenly prone on an ice surface will.
