Would George really be OK with HBO retconning the ending of his own series, before he even gets to write it himself no less? Are my expectations of him too high by assuming he'd have a problem with that?
Also, re-introducing the White Walkers after it was established they all died during the Long Night is getting dangerously close to "Somehow, Palpatine returned" territory. At this point I'm half-expecting the Night King's return to be announced on Fortnite.