Since leaks season is in full force and many players speculate that we will get next expansion announcement in the next month or two, I think we could write our predictions about 10.0 here and compare later, when we get official info about it. Whoever gets most things right, wins 100(!!!) internet points.

So here goes me-

Theme: Similarly to most leakers, I think that the next expansion will be centered around the Dragon Isles(or at least a huge part of it will be). Main antagonists will be Infinite Dragonflight and possibly the forces of Void(which would later tie us into 11.0 Light vs Void). Undermine might also make an appearance as one of the zones.

Name: Something with either Dragons or Aspects in it. My bet is on the simple "Dragon Isles".

World Revamp: No, I don't think we're getting a major world revamp, not on the level of Cata, anyway. Maybe they'll continue to revamp a zone or two per expansion, the same way they did with Arathi and Darkshore in BFA.

New Class: Yes, I think that we're going to get a new class, something connected to Dragons, obviously. My prediction is that it's going to have the following roles- Tank, Healer, Caster DPS.

New Race: Possibly. Yes. We already have wolfmen, foxmen and cowmen, I think it's possible that we'll get lizzardmen next(humanoid reptiles, completely new models that we haven't seen before).

Power progression system: IMO, there will be no PPS similar to the AP farm for the Artifact weapons and HoA that we had in the past.

Player/Guild housing: No, I don't think that they'll add housing.

Other features:

I think that the most important one is going to be cross-faction play. The factions are to stay as they are, but we will be able to pvp, run m+ and raids with people of the opposite faction.

Solo queue arenas. They are testing a variation of it already as a brawl in 9.2, I think for the next expansion we'll get it as a full-scale feature.

I also think that on top of Titles for the top % of M+ players, they will also add a seasonal mount, similar to the Gladiator's mount, maybe even a recolor of it.

Something else I think that we'll see, is some variation of Thorgast. 1-5 players pve content with power ups similar to Anima Powers.

We'll probably get some variation of Class Halls/Covenants, but purely story/cosmetic based, without player power tied to this choice.