I really expected something very different from Argus. Eredath and the Antoran Wastes did not dissapoint me and they could have been entire zones and you could have set up Light and Void forces to help us win the war in the Legion's home turf. I hoped there would be a Suramar-like zone of Eredar architecture in the Red/Gold/Black scheme of the WoD Sargerei were we would be infilitrating a capital (also hoped that Velen's wife Nuuri was still alive and replaced him in the Triumvirate alongside KJ and Archi)
And I did want some worldwide invasion. Broken Isles were a succesful expansion continent but the plot of Legion could have happened all over Azeroth, picking several zones across four continents (Kalimdor, EK, Northrend and Pandaria) to visually update (like Arathi) and having the pre-expansion event invasions be something that lasted the entire expac with possible Legion raids of capital cities (we know at least Exodar and Thunder Bluff were invaded). Then the Pillars could have been all over the world instead of all being in one place.