1. Garrison wasn't a problem for me, lack of content to do outside was (also later introduced gold mission, but it was just desperate act to keep subs).
2. Loved Legiondaries, it was great incentive to do many types of content, especially liked that in encourage you to do just emissary without need to grind all world quest. Only thing I would change is option to target next legenadary, I would prefer it over SL legendary system.
3. Sorry, I loved artifact system as well, especially during 7.0.
4. Yep, Azerite gear was shit for min-maxers and at best neutral for others. Only positive I see is first breach into post-titanforging world.
5. Again, loved Essences, it wasn't best system, but encouraged you to do different stuff like Legiondaries and that's big + for me. I wish I had more time to invest into rank 4 achiev + title, this will be veeeery rare in future expansions. And yeah, lack of catch up in early 8.3 was bad, no doubt about that.
6. Sadly corruption has lot more negatives than positivies as well, this changed my BfA (personal, I play Fury so class problems didn't affect me) score from 'good' (after 8.2) to 'mediocre' among WoW expansions.
Also I don't trust blindly Blizzard, but one thing I know - I had fun on launch with every expansion including WoD (bare technical difficulties); if some patch will be unfun for me (it's not only on Blizzard, sometimes we just burnout for few months), I'll just take break from WoW without creating drama. Am I doing something wrong?