We can already see the changes Larian had to make, goblins have 3 times the hp and half the AC, to accommodate surfaces, and to accommodate their ridiculous height 3:1 advantage system
They're going to have to rebalance concentration as a result as well, which will rebalance concentration spells, which will...
this is just going to be a spiral of them gutting the system they were given to use, and it's going to be unrecognizable by launch (battles already feel more like Divinity than D&D, the game really wants you to just shit fire everywhere and burn your enemies out)
You're not really being smart about this are you?
You know Larian has to balance for multiple things and there are some things that 5e is not good with and some things that 5e is like any fucking system -- in short: context matters a lot and balance is always contextual.
As Abits mentioned the changes were most likely to ramp up difficulty while keeping the encounter number low, you can probably then imagine why they would want to keep the encounter number low.
You can also see how the other battles NOT involving goblins turns out. Guess what? A LOT less surface effects and a lot less manipulation of height.
Try looking at it from their shoes or what possible perspectives may have caused them to do so before going full drool cup.
