Hints lead to some sort of Sylvanas "justification", how should such plot go?

For that, the Horde would have to be wiped out, all Horde lands taken by the Alliance and all horde souls tortured in the maw. Also the Hprde would have to be ignored afterwards.

Tyrande killing Sylvanas and Nathanos and freeing all of her people from the maw would have been fine.
Also getting Ashenvale back and a new home. All of those things were denied and the Night Elf revenge plot cancelled entirely.

We’re even told that genocide isn’t evil. Imagine if the Alliance wiped out every single Horde man, woman and child and were glorified as heroes for that too, just like Sylvanas.
That’s what would make things even, but I have yet to see a single person ask for that. We just want some justice.