You may feel that it makes for a completely different gameplay experience - and you’re right, it does, but it’s still dungeons and Blizzard has placed one thing later in the progression path than another.
Heroic dungeon is to M0 what LFR is to Normal as well: Queueable, lower gear, same content.
No, they haven’t done that, either. M+ was always the extension of the dungeon system, which is why it is named after the highest difficulty level in dungeons with a plus added at the end.
What they have done now is they have removed timers for lower levels. Timers are not necessary at low levels because the challenge is more often than not going to come from just being unable to defeat the encounter because you’re not using your spells, not because of rushing and trying to find out when to use them across many pulls.
There is no massive group of angry people. Not even the OP is complaining about that - he’s complaining about the fact that everything he got has been made worthless, which is true but has nothing to do with whether what he was doing was called M0 or M+ 2-9, and he’s complaining about the lockout, which I think is totally legitimate. There is no reason why +2 should be available an infinite amount of times while +0 isn’t. It actually makes no sense.
When this change was announced the feedback was overwhelmingly positive from just about everybody.
The hardcore is the group of people who are the most active, committed, or strict members of the playerbase.
By definition being hardcore requires a lot of time, which is why i called my own guild Silverblade a casual guild despite it being top 1500 in the world. Why? Because we played 6 hours a week and there was no requirement to dedicate a huge amount of time as long as you delivered on raid night well enough. 9.1 killed the guild because it tied player power too much to grinding dailies. We couldn’t deal with that, too many got frustrated.
Hardcore != good, good != hardcore. There is a correlation because more time spent doing a thing means more practice, but with a game of this age you can find lots of great casuals.
Players who spend inordinate amounts of time in the game yet decide not to play difficult content are still hardcore, they’re just… well, they’re not even necessarily bad; sometimes they’re just scared or disinterested. But the vast majority of players are both casual and “bad” compared to the hardcore and they don’t want to deal with mechanics designed for the hardcore.
They want to explore and experience content with a little bit of pushback to make sure they don’t see everything immediately. They’re not interested in caps or lockouts or DPS meters, WoW has done a VERY poor job of serving these people, it’s now a little better, but it’s still not good enough. Delves will probably help a little bit more, and this did, too.
You and Tyssera just don’t know what it means. It doesn’t mean good, it means ultra dedicated people who spend a lot of time on it.