I hope many don't disagree with the idea of toning things down again and telling more meaningful and relatable stories is the best direction to go in once this trilogy is finished. The last thing I'd want is for this to be a jumping off point where Azeroth and its defining elements are almost or entirely abandoned.
I know I'm late to the faction talk here, but my fear that I feel is increasingly justified is that their poor handling of faction conflict in BfA and even MoP will lead to them just disintegrating the factions altogether and not filling that gaping hole with anything else. Not just throwing the baby out with the bathwater, but torching the whole house. They've poisoned so many wells now that they've conditioned the audience into demanding something new (and the replacement has not been up to par), instead of fixing the damn wells.
We have enough examples from recent expansions that execution is their Achilles heel, not scope or concept in and of themselves. They've taken very large scale, universe-level threats and made them utterly dull and boring. They've created relatively low level and self-contained stories like Drustvar and made them highlights of the entire game.
Personally, I don't enjoy the cosmic storyline because I feel like it's been primarily executed as characters arguing over flimsily defined metaphysics without giving the average player a proper reason to care. My fear is that Blizzard wants to adopt it as the main focus of the story because they look back at what they themselves wrote in BfA and go "but if we wrote about the factions again, we'd have to do a genocidal struggle for existence, no way!" and they go back to characters screaming about capital letter Concepts. I don't think power creep is as necessary for believability as some people make it out to be.
I want a world where the factions show up as the major players in the world that they are and operate more akin to their vanilla dynamics: loose conglomeration of races with their own dealings and agendas, but generally united in the name of good. Remind people of the WC3/vanilla Horde and not one that just consists of nervous Sylvanas/Forsaken apologetics and shove the war crimes villain bat into a closet instead of giving the Alliance a concussion with it.
This isn't saying that every villain needs to be kobolds and murlocs, that's reductionist as all hell. It's just worth analyzing the difference in execution between something like the Cult of the Damned and the Primalists. Antagonists and conflicts that feel more grounded than abstract battles for cosmic dominance. They can make smaller scale stories work and they have in the past, but if the excuse for them not even trying is "they will write it badly", then that just makes someone wonder why they're even here.
This is half me rambling without coffee and agreeing with your general points, not meant to be any kind of rebuttal FWIW.