I've enjoyed it a lot, but I'm starting to see some frayed edges that concern me in general about the lasting appeal of the expansion.
Suramar begins wonderfully, but quickly becomes either highly irritating or just poor Vanilla / BC style quest chains.
No queue for Mythics and Heroics being arguably easier than Normals becomes a mess of having to negotiate with people over item levels and achievements. I'd rather just find a raiding guild and be done with it.
Scaling in general makes revisiting zones kind of blow. There's a really poor spot between dinging 110 and hitting 810-820 ilvl where regular ass mobs will just beat the shit out of you.
Class Halls: I was willing to give them the benefit of the doubt based on the changes being touted in comparison to Garrisons, but the "do Mission 5/10/whatever times" being a time gated thing preventing you from completing their storyline until well after dinging 110 feels really bad.
That said, I've made so much gold off of impatient people buying herbs / ore that it'll probably be a little while before I need to actually pay for a sub.