Oh. My. God.
This is precisely and exactly what I've been arguing as a flaw in 5e's design since before it was even CALLED 5e.
Twelve years now, I've been told I'm crazy. Hateful. Biased. "White room"ing. Etc., etc., ad nauseam.
Now it's literally coming straight from the horse's mouth. Will folks retract any of that? Hell no!
I didn't think you were crazy.
4E has a similar problem to 5E though.
The problem is modern design and the differences between casuals and hard core players. ENworld mostly consists of hard core players.
Every edition has its usual mob of cheer leaders who claim its flawless. Ironically 3.5 lacked that cheerleader mob. ENworlds its mostly 1-3 posters and theyre more relentless optimism.
I suspect im be of the few here who's run 5.5 alot. I also suspect im one of the few who has run AD&D material last year or so and 5.5 and 5.0.
To top that off I've been buying and rereading 3.5 and Pathfinder material. Hell I even looked at OD&D. Hell read Shadowdark as well.
Modern D&D has removed a lot of the things that made older D&D play fast. All of them including 5.0 are more complexity.
You want cover every corner from a design PoV. Even 4E can't fix things if players are doing the 4 round adventuring day (1-2 encounters) regardless of what the rules say. 4E had 70+ pages of errata to try and make it work.
Either you have to roll with it, design a new edition or design a game that dumps the entire D&D paradigm. The latter option will probably tank harder than the T-72.
If I designed 6E if you wanted to fix this without making a new OSR game I'm looking at concepts from 3.5, 4E and 5.5. You coukd do it commercial success idk. It would be a simpler game than 3.0-5.5 with elements of OSR. Alot less hit point bloat a'la 4E to 5.5. 3.5 level hp, scaling saves monsters would regain elements stripped from them since 3.5. Parts of 4E may make it in with monster design (eg boss monsters).
Assuming you wanted a D&D game. Rebuilt from ground up could be done dumping dailies entire and going in completely different direction.
Everything from 3.0 onwards would be up for getting scrapped except ascending numbers. I don't have the exact idea of perfect game but the problem is modern design and the complexity/simple slider.