I would not be surprised at all to see a later down the line seperate books on Dispossessed, Free People’s, Wanderers & Darkling Covens.
They each have a decent sized model range coupled with Allegiance Abilities in the Handbook.
It would only stand to reason that they will redo Seraphon later this year and keep the others for next year (allowing them to ‘finish’ all the races by the end of next year.)
It will also remove the need for the Grand Alliance Books.
My prediction for release order this year;
Orruk Warclans Book
Free Cities Book
Ogur Book
Deathrattle/Soulblight Book (either would be cool, I’d prefer Deathrattle)
Everchosen-STD-Darkoath Soup/Seraphon Book (either one first, then the other)
Next year I’ll be guessing in no particular order;
Dispossessed, Wanderers, Free People’s, Kharadron Overlords, Disciples of Tzeentch, Light Elves (which could add in the old High Elf range & Shadow Elves (which could add in the old Dark Elf Range)