I don't like the Tasha's swap because that does undermine the racial traits. They might as well not exist at all if you can just switch whatever you want.
The 18 vs 16 really has to do with certain races getting that +2. Humans could only start with a 17 even if they got an additional +1 from a feat. Only races that have a +2 could start with 18 and that seems very appropriate. Otherwise that +2 doesn't mean anything. Half-Orcs need to be "stronger" and elves need to be "graceful".
My view is that bigger numbers in a fixed category is the least interesting way to differentiate races. Everyone except human has some differing features, and in the tabletop versions you can even portray cultural differences. (Not so much in a game where all the dialogue is pre-written.)
Because of the way bounded accuracy works, it's highly encouraged to match classes to only what your race is already good at, and in some cases, you have to match the subrace as well. Otherwise, you're not "playing optimally". That's not as big a deal for BG 3, but there's no denying that optimization affects players mindsets there as well.
I would find it much more interesting to be able to play an atypical class for the race without feeling like I'm crippling myself mechanics-wise.
