I was a fool to have been blind to human potential!
Honestly, I'm fine with things changing and Teldrassil being burned and the night elves being decimated doesn't bother me at this point. It's what you do with those types of stories that matter. If they actually put in the effort for the night elves to basically scatter and become something of a nomadic people and explore how this affects them, that's enough for me. This would logically push them more towards druidism and one-with-nature aspects, but that can mean a more feral culture in ways as well. Play up that trendy Thanos angle that nature keeps things in balance and that means destruction and death as much as it means creation and life.
Make the entire race akin to the Dunedain Rangers from LotR, roaming the wilds of Azeroth, their connection to the Alliance becoming more of a loose alliance, and taking action as they see fit by the guidance of nature and Elune. Let them be something of a wild card in the Alliance, starting larger trouble from time to time when they act to do what they perceive as right.
If you're going to take away their home, do something with that plot point rather than "they just huddle in Stormwind now."
I guess my TLDR to Blizzard would have been "It's fine to have this huge, drastic changes to the world, so long as you take the victims of the turn of events and
DO SOMETHING."