I agree with OP.

High ground advantages came from DOS 2, and works fine there because it's balanced with other mechanics that allow characters to move easily and teleport themselves and others.

But in BG3 the lack of honing makes it a cheese mechanic.

I would agree if the benefits were more subtle, like:

- Being higher increases range to spells, crossbows, and so on (not to attack rolls or damage).

- Giving movement penalties when walking from low to high ground, and bonuses to move from high to low ground.

- Fall damage being a one hit kill is ok to weaker enemies, but not to cheese enemies like Minthara, Matriarch Spider and so on.

- Being higher giving bonuses in perception tests to spot hidden enemies in lower ground (in future Acts).