As nice as this assumption is, its demonstrably false.
Just presenting edge cases is not a great argument for a game, where you should be able to play with any given party and the balancing is worked out for that. You already see how they had to come up with new ways to circumvent the rebalancing issues they created, namely the abundance of healing potions and food that heals you. Which in is just another factor, that invalidates balance between the classes, as martial classes get another edge over spellcasters. Martials are restrained by their HP normally. But with healing this abundant you dont really need to rest, so they can go all day long with just basic attacks, while spellcasters would be severely hindered in doing anything meaningful.
Surfaces, in a proper implementation of them, have many tactical elements to them. Even in their current implementation, there are the following considerations.
• Do I want to avoid the surface, thus constraining my movement, or do I want to go through them, taking incidental damage.
• If there is not currently a surface on the ground, but I suspect an enemy is capable of applying one, how do I position my characters to minimize the threat from surfaces
And with adjustments (proper tools to deal with surfaces and ideally also a trade off for using them), they would also add.
• Do I want to remove the surface, or perform some other action (A trade off between making the arena less constraining and another action).
• Do I want to apply a surface, or perform some other action.
The first two are really shallow and not really a tactical play. Because as long as the surface is not killing you outright, there is no downside. Healing is abundant and just a BA, so what gives? No trade-off really. Even if 1-2 of your PCs die, just rezz them.
The latter two are just a cascade that becomes necessary because of the implementation of surfaces in the first place. And if they get implemented there will be other stuff to rebalance again.
They make it harder with every step to deliver a balanced experience, as they stumble from one "Fix" to another, all the while a mostly balanced option is ignored. As I said, I love DOS. More fun than I had in a long time. But Larian should not be afraid to (mostly) trust the 5e rules as they are. The people at WOTC had some great ideas there, and they paid off immensely. Make the systems work on PC and in the engine and trust the success that is 5e.
