Frozen_Heart
Hero
I feel it could have worked, it's just the old species wouldn't have been eligible for the mixed traits system. They could still be played as they were. But yeah it's too late now, the book is finalised.Conceptually, I got no problem with that. But 5e has over 50 species* at this time, and they're not built for this. It would require yet another gutting and overhaul of the species system and a major blow to backwards compatibility. (Such that it is).
You'd have to rebuild and rebalance each species from every sourcebook, including the setting specific ones. That's a massive undertaking. Probably a sourcebook dedicated to it alone. Of course, you could cut down on the workload by ignoring certain options (no half-warforged or half-kender) but you're pretty much recreating the "legitimate" and "illegitimate" combos problem again, just with a wider net.
I just think such a system is about 11 years too late for 5e. The species system is already a mess with the changes from pre-Tasha to now (with several species never having been updated to the MotM standard and others now no longer matching the 24 power level). The internal logic is not there and it would need a whole rebuild to make it work.
And I just don't know if or when we'll see that.
* Depending on the sources and how you define certain options, such as the change to how subraces are handled.
And that's all ignoring the fact that WotC evidently finds the very existence of mixed species people to be 'problematic'.