Spelljammer will return, and maybe even we will see an oficial crossover with Fortnite (OK, I was kidding).
The races have appeared in the last UA playtesting, and this a good sign. Maybe we will see a second UA for other PC races.
I guess the fraals will appear in the setting, but after the handbook of psionic powers. (Yes, they were in AD&D).
The sesheyans appeared in Dragon Magazine #251 as race for D&D. They can fly, or glade at least, but they aren't very good about this and they get tired too soon.
There is a potential market, the fandom who love sci-fi franchises (Halo, Mass-Effect, Starcraft, Farscape, Andromedad, Babylon 5, Galactica). And WotC needs to show an alternative to Paizo's Starfinder.