This has probably always been the case late in an expansion, but it's hard to tell because I've never stopped playing early in an expansion before. But getting fully caught up in Shadowlands really took very little time. There is no question that the new zone in Zereth Mortis and the quests associated with it were designed to make that happen very quickly. With fairly limited play time because of my IRL schedule, I was basically caught up within two weeks, have unlocked flying in both the Shadowlands and Zereth Mortis, and am geared enough that I've run about half of Sepulcher in LFR.
I'm still playing as Destro, because I love the AOE abilities that it offers on the large trash pulls in Sepulcher, although I'm still not fully gear optimized for that. I've finished the first two wings and also picked up my first tier piece. I'm still working through the full Zereth Mortis storyline and knocking out the world quests there each day. Having flying unlocked now will certainly help a lot with that.
Unlocking flying was surprisingly straightforward. The only challenging part was getting through the 10 rares achievements. With most folks having flying unlocked now, it required some degree of luck to have rares spawn nearby. Otherwise, they were generally dead before I was able to get there. It wasn't impossible, it just took some patience.
The only negative that I've seen so far is that with the newest patches, they seem to have taken an expansion that was already overloaded with too many currencies and game systems and added a few more. Hopefully, they will learn to dial that back a bit in the next expansion.
After I finish Sepulcher on Joar and the Zereth Mortis storyline, I may go back and finish leveling the two members of the original five that I never finished when Shadowlands was first released - my Death Knight and my Druid. We'll see if either of those is any easier than it was then.
That's it for now.