I have no issue with getting rid of the "half-X" terminology. It's why I've generally shifted to referring to Half-elves as Khoravar and Half-orcs as Jhorgun'taal, though those terms are specific to Eberron.
I have no problem with opening up the species combinations either. I have no desire to lock that down again.
But I do think there needs to be a mechanical aspect to mixed ancestry characters for people to play with, even if it's only optional - it's an important aspect to my character creation process and how I relate to the characters I create. Without it, they don't actually feel mixed ancestry to me, and that means that the goal of mixed ancestry representation is only being met at the cosmetic level.
More to the point, in the name of "balance" and sticking it to hypothetical min-maxers (for surely the concerns of mechanically minded players can be for no other reason), the ability to actually play a mixed ancestry character has not only not really been increased, it has actually been diminished, because functionally there are no mixed ancestry characters anymore, just characters that look the part. And that, I feel, is not sufficient.
I'm sorry my go-to example isn't interesting enough to be worth considering.