But, that works both ways. The current system does not support the "pick a parent" system. Since "Pick a parent" results in mixed heritage characters that are virtually indistinguishable from 2014 races, I'm failing to see the problem.
Because as shocking as this may be to hear, I care about more than just the mechanics. I care about how those mechanics are derived and I care about the story that process tells.
The story that "pick-a-parent" tells is:
"Oh, you want to play a Khoravar? Well, that's basically just an elf anyway, so here's an elf statblock - you lose the 'human' part because you don't get Skill Versatility anymore, but you get everything else the old 'half-elf' used to have plus the rest of the fancy elf traits on top of that, so really you're coming out ahead there. Just say your ears are a bit less pointy and you're good to go."
"Oh, you want to play a Jhor'guntaal? Congrats, you're an orc now! I guess you can file down your tusks a bit if you want, but doesn't that feel so much better than pretending your character was part human?"
"Mixed ancestry is fine, so long as only one of those ancestries matters."
The fact that the nearly all of the traits of the '14 "half-elf" come from the '14 elf mechanics is a failure of the 2014 design (and a sign of how non-existent '14 human mechanics were), not proof that they should simply be elves with the serial numbers filed off. I don't want to simply replicate the '14 "half-elf" mechanics. If I did, I'd just use continue using the old "half-elf" - my old books aren't going anywhere, and it's supposed to still be compatible.
What I want is a '24 Khoravar (or insert other appropriate name here) that blends traits from both the '24 human and '24 elf into a cohesive and distinct whole that is roughly in line with the current design for species mechanics, and/or an (optional) set of guidelines detailed within the core rules showing the process of how to do that myself so that any mixed ancestry can get the same treatment for those who find "pick-a-parent" insufficient for its stated purpose.
I know the mechanics of the "half-elf" have historically been rather boring - I am not pretending otherwise. So let's have a discussion about how to make them exciting, not throw them in the bin and tell every Khoravar player that they should be happy to be playing elves now.
Personally, I honestly don't care about specific mechanics, I prefer to discus tropes, vibes, and the like. Because, if we're going to talk about the mechanics...
Then we have to address the elephant in the room. Mainly, the greatest mechanical appeal of the half-elf was the fact that they had +2 CHA and two floating +1s (total of 4, matched only by mountain dwarves). Not only did 5e have an abundance of CHA classes, but half-elf was seen as the bard-elf type (as opposed to high elf wizard, wood elf ranger/druid, and drow assassin). Thus the +2 CHA when most elves are surprsingly non-charisma. The skill versatility as well was a nod to bard being the half-elf signature class rather than human ancestry.
Now? You can't get a total of +4 stats on a species, and everyone has flexible stats. This immediate association with bard isn't a big deal anymore, given that 5.5e has moved away from molding their species into having a singular favored class direction. Immediately, what has proped up the half-elf's "mechanical identity," to borrow a term from elsewhere on these forums, has immediately dissolved. Darkvision and a resistance are common other species. Which means the only thing really of note about the half elf? Two extra skills. Ngl, nothing to sneer at, but nothing amazing either. And as I posted earlier, it's trivial to make a muggle elf that gets skills instead of spells.
Half-elf has dropped from being one of the best species options in the game... to potentially being the absolute worst, much as it was in 3e. Its much like the 5e sorcerer problem. If everyone is a flexible caster... then what is the sorcerer's gimmick? You need to reinvent them from the ground up.
So, that's where the half-elf is in 5.5e right now. In dire need of a reimagining, because mechanically its in pretty bad shape.
So let them be reimagined into something that can stand on its own - bring their mechanics up to par with current species design or give me the tools to do it myself. That's what I've been saying all along.