I gotta say, I'm super hyped for this trilogy.
I'm also curious about the road they're taking some things. Like for example "bringing the various elven tribes together" ... That certainly sounds to me like all types of elves coming together once more to fight the big bad, whom in my opinion, makes the most sense to be Azshara, who ruled over all of them in the past, she's the unifier.
With cross-faction guilds, dungeons, raids, now warbands showing characters from different faction in the same warband ... the elven tribes coming together. To me that's eerily close to suggesting we might see a world where factions ultimately don't matter.
Also, I love how we're kind of rebuilding this idea of several human kingdoms. Before, Lordaeron was the religious and spiritual capital of the human kingdoms. Now, it seems this Arathi kingdom might replace it, becoming the human kindgom that thematically represents the religious/church of holy light side of human culture. With Stormwind, Gilneas, Dalaran, Kul Tiras, Hallowfall, it'd be cool to see a new coalition of human kingdoms as a unified front, like the Alliance of Lordaeron was at one point. I'd love to see Dalaran as a fleshed out, distinct kingdom, with its own playable allied race with distinct features. Same for Hallowfall humans, whom I'm very interested in seeing if they look any different from regular stormwind humans.
Also, considering Anduin left the throne in Stormwind, and that his internal struggle has to do with his connection to the light. I wouldn't be surprised if we saw him lead these new hallowfall humans. Either him or Turalyon, since they both are very connected to the light.