Even though i'm still playing and the guild is still going strong, i wasn't excited for Shadowlands, nor does it excite me still the way FFXIV story patches and expansions, but it's doing enough to keep us around.
Personally though, i think it's terrible. The seperated zones, the flying through oribos, the no mount maw unless you do boring torghast ad-nauseum. The maw itself, terrible. The raid and dungeons, probably the worst i can remember. Covenant balance turned out as bad as expected. But, i don't know... guild is still here and i don't hate it. So, i guess it's average.
I suppose the removal of the most cancerous systems from the last 2 xpacs (infinite AP ground and war/titanforging/corruption) made it tolerable. So, while it isn't exciting, it isn't abhorable either. You can choose to not do the boring stuff. That is actually quite important. Classes are not terrible anymore either.
Lets say the essential is there, even if not great. Lots of boring systems that need re-thinking (world quests for example). Story is just dreadful. Like outright bad compared to the competition. They need to keep the core they now fixed, cut these boring systems and choose something to focus on and improve. I would start with storytelling and the single player experience.