Regarding your first paragraph, as stated before, I think that’s an unfair standard for suggestions generally. The nature of suggestions in general assumes that something is wrong and needs to change. Forcing people to engage in Battleground or Raid content if they are endgame PVErs or PVPers respectively ranks among the items that I think are wrong and need to change.
Regarding your second, you mention relevance to what an expansion’s story would be. That’s another item that I take issue with. I prefer the vanilla model - where you can have a conflict in Ashenvale, an only marginally connected issue in Arathi, a completely disconnected conflict in Silithus, Dragons in the Burning Steppes to go fight, Demons in the blasted lands. Which of these concerns is the most important and should attract your attention? That should be up to you.
This is a world. It in no way needs to be wrapped up in a single, all encompassing expansion narrative - and I would argue that the game was better when it wasn’t.
One final note about Cataclysm: I think you’re referring to Malfurion and the Druids’ refusal to even comment on what was happening in Ashenvale. That is a different thing from having disconnected conflicts. No one wondered why the characters in Uldum didn’t seem to be concerned with the faction war - but none of them were the co-leaders of a playable race whose lands were being invaded. There’s important context missing from the application of that situation to the principle.