Turned themselves into yet another tree, funniest shit I've ever seen.
Enough of these fucking trees, they have a 100% failure rate and even Teldrassil was an unspeakable bete noir which only got any sort of emotional weight when the Horde torched it and then became a black hole of undeserved pathos for half a decade by this point. The only good tree was Nordrassil and it too was destroyed in its first appearance. The entire premise of the WC3 campaign was to let go of their singular dumb tree and this point has been missed for their entire WoW existence. Yet every expansion introduces a new failed tree and the night elves spending an inordinate amount of their time dealing with it.
The idea of the Night Elf spirits going back and contributing to their people instead of being fine to frolic in the woods is a good call, but given they're playing with the wisp angle of spirits forming new life with this anyway, having them be wisps proper would be more direct and interesting and allow the night elves to carry on instead of jogging in place. Besides, we all know that the reason this tree isn't immediately planted and grown is because we'll have Tyrande go around in Explosion of Dragons collecting gym badges from the dragons to empower her new and improved tree.