I think one of the reasons pre-BC was so immersive and memorable (not that I still play that shit again, 3 characters was enough) is because there was no overarching theme being shoved down your throat at every corner.
- We're fighting the burning legion and this quest is telling you that you're fighting the burning legion which you need to fight...burning legion!
- We're fighting the scourge and this quest is telling you that you're fighting the scourge which you need to fight...scourge!
- We're fighting the old gods and this quest is telling you that you're fighting the old gods which you need to fight...old gods!
It was more like "hey dipshit, i'm a bigger dipshit than you and i'm in trouble, can u help plz?" with varied storylines from zone to zone, sometimes spilling over into other zones, but not that often.
And when you did stumble on a bigger quest like saving Bolvar and going to fight Onyxia, it came out of nowhere and you had no idea what to expect at the end of it. You'd be like "OH, that's why I sometimes see fucking dragons in the throne room, it's THIS quest! Omg I'm doing THAT THING!".
I think it would be a nice change of pace for everyone's big bad fatigue to just be thrown into a sandbox of stories and enjoy adventuring again.