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.
There is always a trade-off in order to achieve something, even if the trade-off happens to be time. For example, lets assume they implemented surfaces as they currently are in the EA, then did some focus testing to determine how much they need to improve martials in order to keep the system balanced and then made that implementation. Time was lost while doing this and time is a resource. If you assume time is not sacrificed, that means something else is, unless you assume the developers have perfect knowledge and create a flawless system on the first try without messing anything up. If that was the case, we would not be having this discussion anyhow.
The more complex you make a rule set, the harder it becomes to balance because the more variables there are to adjust for. Sure, its easy to give examples of very simplistic, perfectly balanced games (for example, Rock, Paper, Scissors), but the moment you want to add more depth to a system, you need to sacrifice something.
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. 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.
I was making comparisons between this game and a PVP game (where balance is absolutely the core of the game) to draw attention to the key differences. And sure, whilst any number of monster interactions could be managed to another player, they aren't and they likely never will be, so that is a non analogous comparison because one of the limitations we are imposing on the system by having it within a computer game is that it is controlled by a computer and there are massive differences between a computer and a real person. For one, the computer can only react to situations it has been programmed to deal with, its a very narrow "intelligence" (if you can even call it that) with a whole lot of limitations and a creative player can easily bypass those limitations. This is incidentally why a player can get away with killing that entire goblin camp in the first place, because if it was a vindictive player controlling those goblins, the players would be very, very dead.
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.
I think it depends on a few factors. If there was a surface that did 200d10 damage for example every round, even if it took you 3 rounds to remove it, you would probably make removing it a high priority. They could also scale fire surfaces at a high level by increasing the damage of surfaces as the player level increased. We don't really know what they are planning to do beyond spell level 2 right now and there are lots of ways which surfaces could become far more broken, or far more underwhelming. I mentioned above why I like surfaces, its possible to include them, without completely skewing balance. Although I acknowledge that even if they are made inefficient action wise to apply, by virtue of being there they make casters stronger by giving them more options.
An example I saw mentioned somewhere which I personally liked is if targeting the ground created a surface but targeting an enemy did not. This creates a situation where a player needs to decide whether they want the surface, or the direct damage and keeps the surface dynamics in the game. They could up the cantrip surface damage to say 1d6 if a player throws it on the ground and have it deal 1d10 fire damage directly. If the AI walks through the fire, it has a potential to maybe do more than 1d10 (I have seen some enemies do weird stuff on flaming ground which resulted in them taking 3+ ticks for example) and so it has a potential to do more but also a potential to do nothing.
