Right now, the void elves simply aren't enough on their own to pose much of a threat, and they don't have enough sway in the Alliance to get many allies. But with the high elves joining them, they could actually accomplish something. They probably wouldn't be able to actually take back their homelands, but they might at least land a few blows in the sin'dorei pride. With the night elves joining them, they might even be able to cause some damage. And perhaps some of the ren'- and quel'dorei could reach their old homes and get some of their old belongings back. And disturb the blood elves enough to draw their attention away from fighting for the Horde on other fronts. So many stories to tell, and not enough playable elves to do it with. Yet.