I do.
Compared to virtually any other modern TTRPG, 5E is massively more demanding prep-wise and significantly more annoying to come up with stuff for on the fly. It's just not at all well-designed for it. It's not even as well-designed as 4E for it. There's a whole pile of stuff you're supposed to do for 5E, and the game benefits heavily from actually doing it (encounter design, detailed map design, traps and hazards, treasure and loot, NPC design, etc. etc.) none of which 5E handles with much grace.
If you're comparing to 3E or PF1, yeah it's not as bad as that in many cases, but that's kind of a crazy bar, imho. There are only a handful of modern RPGs which even arguably need/benefit more from prep than 5E.
So I think it's a huge issue myself. Esp. given 4E was significantly less of a pain here.
Pretty much exactly what I'm looking for. And yeah, the playtest has indeed been profoundly boring so far, which is probably good for compatibility hopes, but not so great from the perspective of making D&D a better or more interesting game.