Gonna lay down some heavy plot predictions probably like… 5 years in advance here.
I’ve played this game long enough to know that if, or more likely when, we end up going to the Arathi Empire, we’ll likely find ourselves allying with a dissenting group of Arathi (likely similar in motivation or related to the rebellions that General Steelstrike mentions having helped to defeat before arriving in Hallowfall) when we arrive there.
It also feels like a safe bet to say that unless Blizz wants to turn them into an overarching Xal’atath/Iridikron-type villain, that the Arathi Emperor will probably be the last boss of the first or second raid before they pan the camera back and show that the Light is doing some wacky stuff on a cosmic scale in the area.
If I had to make a prediction on what that “wacky stuff” entails, I’d say that helping the Light win Renilash (possibly in Midnight) is gonna be a MAJOR mistake on our end, as the war between the Light and Void was never supposed to end, and without the Legion or the Void standing in their way, the Light’s forces will turn their conquest onto the rest of the universe.
This’ll probably all include an appearance from the Realm of Light (mentioned in an old Shadowlands Danuser interview), the Scarlet Crusade, Yrel and her army (since Cosmological Forces transcend timelines, as seen with Death, Order, and Chaos), and possibly an appearance from Tirion and Uther’s souls (since the Light wouldn’t let the DKs turn Tirion into a Horseman in Legion, and Uther is literally split between two soul fragments).
And maybe a mention/cameo from Crusader Bridenbrad’s soul if they remember to.
Bonus: We could potentially also see the return of Sire Denathrius in this Arathi Expansion, as Lothraxion (the Light-forged Nathrezim) still exists. Not as likely as everything else that I mentioned, but worth noting.
Bonus 2: Calling it now, Amitus, the Peacekeeper (the Light Titan from Hearthstone) is gonna be canon, and if she doesn’t debut in The Last Titan, then she will here.