So let me try here: OP, what exactly should be made for it to be a Baldur's Gate 3?
Not the OP but its rather simple, implement 5e faithfully, Larian promised the game would operate on the 5e ruleset. Its hard to even recognize the relation to 5e at this point, its probably even worse for some of the old school BG players cause they hoped the game would be 2nd Edition. The simple answer you are looking for is this: it is not a faithful adaption of either 2nd Edition (for the Old Guard) and not a faithful adaption of 5e (for the New Guard).
The expectations were to not find a hybrid of DoS and DnD but to find DnD with changes made so the ruleset would work in a video game.
And no, none of the changes they have made so far are required for a video game, a good example of a very faithful implementation is Solasta, which is pretty much 5e and works like a charm.
