To get back to Classic for a bit, this is what I think is happening. Players who prefer the old ways (and full disclosure, I'd count myself among them, but to a smaller degree than most) complain/talk about the negative sides of modern WoW and Battle for Azeroth in general. While they do this they also talk about how things were better before and often mention Vanilla as a reference point. People who enjoy BfA now feel attacked by this and so they retaliate. Hence, liking Classic means you either have nostalgia goggles on or have no idea what you're talking about and will hate the same things you say you want 2 weeks after you start playing it. It's an amazing thing, where literally each side is doing to the other what they feel is being (wrongly) done to them. I feel like writing this is the most redundant thing I've ever done, and yet I also feel that it needs to be said, because it seems some people just don't get what they're doing, or at least I hope they don't (some do and are doing it on purpose but there's trolls everywhere so there's no point in even discussing them).
Most people come here not to read walls of text, they look for the better-rated strategies that match their pet collections, copy&paste stuff they need to import into their addons and only come back if something goes horribly wrong and then mostly to find help in other peoples' comments who also struggled or to find a different team/strategy: I don't think many people wanna read about stuff that already happened to them, they mostly want to see solutions and it's the best way to have them in a well-optimized strategy&team already.
Logging in for the first time, being welcomed by THAT login screen and THAT music... You can't not be taken back if you've played Vanilla, and especially if you've played 2 years of it non-stop all day every day. I probably stayed 10 minutes in character creation just because of the music alone (and trying to get my character looking exactly as it did back then - although I wasn't a shaman then). The whole intro experience was especially amazing for me since the Tauren starting zone was my first encounter with WoW in the EU beta, and a little bit of that spark did return. But is that all Classic has to offer? A trip back in time when we were wowed by the game for the very first time?
The fact that Cookie's Tenderizer from the Deadmines had +3 instead of +2 strength. The fact that the Stormwind south bank had one instead of two mailboxes. The fact that Jaina's Proudmore's name was "Jaina Proudmore" instead of "Jaina Proudless." Stuff like this isn't what mattered. It was arbitrary. If Cookie had dropped a shield instead of a mace and Jaina had been named Susan, nobody would have cared. It wasn't specific details like these that caused us to enjoy the game.
Instead of sharding the zones, their plan is to shard the entire continent at launch. In Classic WoW, there are no dynamic spawns and questing in starting zones would quickly become annoying, so it's understandable that the game is all but fun when there are no mobs to kill, but layering will also cause you to see new players, every time you sign in to the game, which is a clear downside of the tech.