For me it is a return of immersion. Like Talent Tree Revamp and Professions update might help for this alot ngl.
I do hope we got a proper return of Weather effects, the rain effect on Classic WoW is still sooo much better then retail.
Same with snowstorm and other weather effects.
A return of more casual stuff to do outdoor, that isn't WQ, example real WPvP or fun events. A reason for us to do something.
What would you wanna see improved in Dragonflight?