A lot of things are done right and after the last two blunders, this expansion has renewed some fun in WoW! The main issues I do have with it are...
The new talent trees are more complicated than the original ones, which offers a lot of annoying branches to consider as well as two trees to spec out core class and spec talents. Not necessarily a bad idea and good UX, just perhaps a bit too much away from the lackluster MoP talent revamp we've had for the last 10 years, and even further from the original talent trees.
Dragon riding for the most part is a lot of fun and a great addition. However, it feels punishing when you can't get a high enough vantage point to start from because you have limited abilities that only charge if not flying or if flying fast. The idea is better than typical flying mounts, just needs more polish. Also, they need to let you use them outside of the dragon isles. It's weird that you can't but regular flying mounts are allowed!?
The continent doesn't feel that diverse and is only... 3 zones? Perhaps you can count the Dracthyr starting zone but still, it's less than even Shadowlands! We have a volcano-ish jungle, plains, forest, and a mountainish forest(?); Which are different but similar at least visually. Draenor zones were very different, BFA zones were different, Legion were different... Even Shadowlands offered more visual diversity. Don't get me wrong, I still enjoy the zones for what they are, just could be a bit more varied.
Dracthyr is neat, though their heads seem kinda small and they can only be one class. Something I understand why, but kinda sucks if you don't enjoy the class. The humanoid forms are annoyingly weird/ugly. They should have just let you choose any of the current races like literally all dragonflight dragons can do.
The story is... Okay. This was suppose to be us going back to simpler adventure-focused stories but instead, big bad people that just happened to start bad stuff now and Dracthyr beg our faction leaders for help like we're some mindless peons of theirs instead of just asking us directly. I'd rather there be focus on the dragon flight history, their rebuilding, learning of the other inhabitants, more titan lore, etc than some salty anti-Titan dragonflight genociding their own cause...!?
There's also a lot of pandering this expansion. I like homosexual relationships (I'm gay) and general additions like the a deaf leader and normalizing strong women, but they do this to an excessive amount and to a point where it's basically their personality/power. It should be flavoring and to balance things out, but instead it's just an excuse.
Dragonflight is an expansion that you'll likely have fun in and is a step in the right direction, but definitely concerning that they're doing typical media tropes with marginalized people and recycling the same tired stories. I don't regret getting it and will still play it out, just still not as good as prior expansions like Legion.