It's was D&D.A “drastic shift” is a bad idea. When people buy a game called D&D they expect to be able to play D&D, not some other game, no matter how good it is.
It just was with 10 fixes when the community was ready for 5 in 2008.
In 2025 today, the community wanted all 10 of 4e fixes (playtested better of course).
That's the fundamental problem that D&D has. Everybody knows what the issue is when it comes to bosses. The problem is that mandating them in the rules requires a heavy shift of the gameplay. The issue is that many people don't like what the problem looks like so they rather keep the same old and kludge it afterwards while complaining why the kludge is not in the bay system even though they won't like it if you put the fix in the base system.
No Take. Only throw. Says the dog