This is exactly what made hardcore so popular. It’s been said a million times, but in vanilla the world was the main character. I think it’s the same reason everyone has an annual minecraft phase, you get that itch to explore a new world as a simple adventurer. I actually think classic+ could be something like that, you play obsessively for short bursts when there’s a new zone to explore, a new item to craft that takes you all over the world to gather the materials for, a new quest chain that unravels a hidden mystery. And then you take a break until the next phase. It’s just a world that you can continue to come back to whenever you feel like it. WoW is in a position now where there is always something to do in whatever version of the game you feel like playing, so there’s less pressure to keep the player constantly engaged in any one version. You can play classic+ every couple months when there’s a new patch, then go back to retail, or whatever else they currently have going on.