I think it’d be tricky to be certain.
For starters, people are attached to their mounts, their pets, their transmog collections, etc… losing all of that would be painful. Assuming this is an actual reboot and not a brand new game with an entirely different engine, porting all of that might not be impossible. Heck, have an Altar of Storms/Altar of Kings in each capital city with Chromie sitting around, or some other Bronze Dragon in disguise, telling you that you’ve inherited something. Ultimately from an AU version of yourself, but still, it’d be a way to carry over some progress.
After that where it’d really get difficult is the selection of playable races. While this would be a good chance to consolidate Allied Races into their Core Race counterparts, the story would have to be adapted for certain races to make sense. It’s not that hard to imagine Vulpera or Pandaren just being scattered around randomly, for example (if anything, its weird how the Vulpera never got beyond Zandalar/Kul Tiras considering we’ve seen them as pirates). By contrast, Draenei didn’t appear on Azeroth until BC, although we had seen Lost Ones around in vanilla, so even that might not be impossible to make work.
The real headache would be Void Elves. A chance to just wipe them off the face of the franchise entirely as the mistake they were, and yet, that’d be the scummiest thing to do to the players whom actually like them despite their flaws. Even then, I don’t think it’s outside the realm of plausibility that a cult of Blood Elves exist that turned their backs on the Light after the Third War, and embraced the Void to the point of transformation. Just… don’t have Lor’themar/Rommath banish them this time.
A reboot does provide opportunity in terms of races as well. If we’re consolidating races under a single banner for character creation purposes, it’d be a good time to add non-playable options, such as Forest Trolls. Ogres could also be added to the game as a playable race.
Dracthyr would be particularly tricky to make work, but the idea of Deathwing having corrupted a bunch of eggs to make soldiers isn’t so far fetched I suppose. It would also be a chance to update their visage form to apply for any playable race, and add in Body Type 3 as Drakkonid or something. Honestly, I’d be sold on them as a kind of spy race that specifically blends in to mortal societies. The player character can walk around as a Dracthyr and it actually puts NPCs are ease knowing they’re not hiding it or something.
