I agree that the old factions and characters have been thoroughly exhausted, but at this point it doesn't matter what characters Blizzard uses; the execution of the writing is still going to be bad. No one cares about the new characters of Calia or Bolvar's daughter or that Nightborne lady or the Primus. People still have an emotional investment in the old characters like Thrall and Anduin, who were created back when the story was still decent. Blizzard mind as well stick with them. When the writing was still decent, new material like Pandaria could be pulled out of thin air and people would like it. But when you have bad writing you get Shadowlands, and people are begging to go back to what is familiar. It seems people would rather have bad writing with characters and factions they at least liked, like BFA, then have bad writing with new characters and factions they never cared about (Shadowlands).