Void Elves are what Worgen should have been, a darker and more sinister aspect of the Alliance that isn’t as nice or “stereotypically heroic” but more of an anti-hero. The devs themselves even said that’s what they would be, but it never came to pass, likely because Cataclysm was a massive bomb of an expansion that failed to live up to expectations.
Worgen should have been the Alliance’s shadow-themed race, as well, because their very first iteration as a concept was in vanilla and most of their NPC’s used shadow magic. It was even part of their lore that shadow was natural to them and they darkened the land by their very presence, all cool concepts that were retconned by the devs for whatever reason.
I doubt it will be a warfront, who will their rival be? Should be Forsaken, but they are already used up as a rival for Night Elves. I guess that leaves Goblins or Blood Elves, I’m sure Blizzard could make up some weird justification for them wanting to take Gilneas, likely strongarmed by Forsaken into doing it while they focus on Darkshore.
Otherwise, it’ll probably just be part of the heritage armor quest-line.