i think it would be hard to find events for the rest of azeroth...
I'm just a lowly lurker, but I'd kindly disagree. For a moment, say all the factions stayed the same. Incorporating the Broken Isles could function as a post-early duel region. For example, say the South Alliance wins the early duel against Fel Horde. Now they can set their sights on the Broken Isles. Stormwind could be given objectives to pursue in Stormheim, especially with the Greymane/Sylvanas conflict that ensued there. Alternatively, Ironforge could pursue other archeological research to bolster its forces. And either of those players could be candidates for interactions with the Valarjar. Another example would be if the Night Elves win the Kalimdor early duel and seek out the Dreamweavers of Val'sharah. Or if the Horde win the early duel, they could seek out the Highmountain Tauren. NA could seek out Azsuna via Dalaran & Quel'thalas relations. And if the Fel Horde won the early duel, they could do something with Alt. Gul'dan and Legion would get stuff from its 3rd Invasion. Scourge could possibly do something with Helya & the Kvaldir or maybe the Fal'dorei?
Or, you could just make it all Neutral / Neutral Hostile and make it a battleground over artifacts that could be made out of the A) actual Artifact Weapons, and B) the Pillars of Creation. Since items have a significant impact on gameplay, this alone I think could spice it up even more.
Or or, if you're looking for stuff that literally goes all around Azeroth, queue in the Class Order Halls. The Silver Hand in the Plaguelands for Lordaeron. The Tirisgarde out of Dalaran. Ebon Blade in Northrend for Stormwind (or the Scourge if you wanna play with events 'n' stuff). Earthen Ring for the Horde out of the Maelstrom. There is a lot that could be done with the Class Order Halls.
Personally, I'd love to see Azeroth Wars with LTF / LTA style faction evolution, but that's a different conversation. My point being is that there are a lot of possibilities that could be done with Broken Isles & Argus. If I was a map maker, I'd attempt to do this, but alas.