Of all the groups done disservice by this plot, I have to actually admit that the Night Elves in general are the least ruined. This isn’t the first genocide the Night Elves have gone through, and they’ve actually bounced back remarkably well. Delaryn, Sira, and the Undead Night Elves that join the Forsaken specifically are certainly ruined in their current states, yes. But for the living Night Elves, though the loss of Teldrassil is sad, are still themselves, and took the fight back to the Horde. Do I want more Night Elf successes after the loss of the War of the Thorns, such as Battlefield: Ashenvale and beyond? Yes. But, asides from potentially being unfairly ignored, Alliance Night Elves and their allies at least have gotten to stay true to themselves, unlike the Horde.
I love Teldrassil. It is still my preferred place to log my characters out at and where to set my hearthstones to. But, the simplest retcon I would go for would simply to have had all of Teldrassil have been evacuated before the burning.
They can even keep the catapults so we have something to laugh at still.