Yes, but In creating 5ed, they went on by asking us through survey and playtests what WE wanted. At this point, they have a.moral obligation to keep their word that this is our edition. If they want to go the 6ed direction, I have absolutely no trouble with that and I would embark on that wagon without second thinking. But a major rework of the 5ed principles such as these (and it goes way deeper than mere npc and monsters) should, no must warrant a new edition. This would make me way happier and a lot more understanding than the perversion they are doing right now.
Personally, 5ed has its flaws and a new edition would solve a lot of these (or might have the potential to do it)
I answered those surveys as well.
Am I part of WE? I sure hope so.
Do they have a moral obligation to provide a 5E that serves what WE wanted, people who answered like I did?
I mean, I read the design stuff. They did talk about many of these issues at the time. The 5e monster creation rules clearly are not "make a PC", and the initial monsters clearly didn't use PC creation rules. I mean, the medium sized spellcasters use d8 HD, for a clear and trivial example. They have never once in any monster manual stated "the leader is an orc with 7 fighter class levels (subclass champion)."
Even clearly subclass inspired 5e monsters, like a diviner, doesn't exactly match the 5e PC subclasses.
If they have an "obligation" to provide the game you asked for when you, personally, answered the surveys, how is that different than the "obligation" they have to provide the game I asked for when I, personally, answered the surveys?
I read the 5e monster building guidelines. They do not say "always use PC rules to make an NPC". The MM doesn't do this. There are some spellcasters with spell lists and slots, and explicit advice that changing which spells they know could impact their CR (but you can be lazy and not bother), but there are also plenty of monsters with abilities that could be spells (DK necrotic fireball) that aren't written up as spells.
Going more that way -- monsters with abilities that look like spells -- together with advice saying "here is how to treat them as spells" is not a rewrite of 5e.