You had me till Azshara raid and then I lost it at Fel Varian.7.1 Karazhan
7.2 Troll Raid - N'zoth endgame
7.3 Kul Tiras - 110 zone much like Suramar, progress against Azshara's forces.
7.4 Azshara raid
7.5 Get ready to deal with the The Tomb of Sargeras
7.6 Tomb of Sargeras raid, Fel Varian + Naisha (The one who got trapped there in WC3), I personally think KJ is gonna be the last boss here but it can be the Avatar of Sargeras as well.
You might think it is too much content for one expansion, but they're now proving to us that they are far ahead with their content. So this is not so far fetched as you might think. It sucks but I just cannot see them doing one more expansion on Azeroth, and Argus has incredible amounts of potential for future expansions though I doubt I'll be playing the game that long!