As someone who has mostly enjoyed BFA (it's not one of the best expansions or anything but i've enjoyed it more than WoD, WotLK and Cata) I kinda fear Blizz will learn the wrong lessons from the overall reception to BFA and Shadowlands might reflect that.
I'm hyped for what I'm seeing in terms of art from Shadowlands - the zones look great, the new instances look cool and all of that feels super exciting. On the flip side I'm not that hyped for the Covenant system because I want to have the option to be optimized for any content I do and Covenants will put a stop to that. I would also want to pick different covenants for alts but knowing some of them will be better than others, that might not even be a realistic option for me.