Voted no.
I mean Horcs only exist because people wanted to play orcs, but D&D orcs were locked behind D&D's weird, terrible legacy when it comes to race that's not getting broken down. So we have orcs just flat out now; there's really no need for half-orcs. And as a plus, we no longer need to play with the unfortunate implications (And more weird bad race stuff) that got put into play to make them exist in the first place.
Frankly, I was pretty happy when the weren't in the initial 4e release because of the 'story' they got saddled with made me dread their presence and that was before we got orcs.
People say they're representation, but as someone they're meant to be representing, not all representation is good representation--and horcs were not good representation.
And half elves...
I honestly don't even know why half elves were a thing. Because Elrond got mentioned as being one off hand in a way that doesn't really get explained? Because someone know Tanis would be written in the future to coin a hot new sad boy? I have no idea. They were like... the sexy species for some reason?
Look, I took the concept of fey descent and descendants who lack the power the defined their ancestors, and ran with it in my own work and I still don't know what the source material or its progenitors was actually trying to do; the last three editions made them 'the bard race', which... okay?
In terms of representation, they're better than horcs, but man... I'd love to see a story of being mixed that's not entirely about how sad I'm supposed to be. And the narrative is so... weird. I've never been rejected by my literal family for being 'half', but by communities who see me as wholly one or the other. I know other people have other experiences, but it's just so off to me. Especially as a species-wide schtick. Who are all these millions of elves and humans who will gladly sleep with the other, but are then shocked that a child of such a union has feature of the other parent?
I don't exactly mind half elves being included and they're not really taking up a slot because unlike classes, we're allowed to get new species. But at the same time, to make something a core species, I feel they need a strong reason for being and helves just don't have it.