I was thinking maybe Warden as the new spec, given that Wardens have a lot of void-like notes. For example Umbra (Shadow) Glaives, Avatar of Vengeance (void like), blink (void like), Shadow Strike (do I have to say it?).
Mechanically I believe Warden is an easy fit, thematically in an unusual way they fit (captors who helped, ish, then escape).
So then you have:
Vengeance → Warden (perfect, warden’s meta is called Avatar of Vengeance, the fit is awkwardly good lol) and felscarred
Havoc → fel and reaver*
Void → Warden and reaver
*(I feel reaver actually fits decently with Vengeance, but I think Warden and Fel fit better, additionally so if reaver is tweaked to flow better in Havoc and Void. Havoc could also have a talent that makes thrown glaives more like glaivesaws (melee short duration high potency dots), potentially giving reaver an entirely unique style on Havoc compared to Void- which would be more ranged based)
Void can be a ranged DH spec, which can be part of the gameplay changes that make the spec more than another can of paint. Additionally it can be the chance to add the ranged form of Illidan to DH.
Also as an aside I think felscarred as a hero tree can be revamped for better theme, as it is sort of the Illidan tree, but currently does little besides improve meta. Quick thought is maybe the first node you select the primary demon soul / demon artifact (like how Illidan powered up), which has heavy impact on your meta. Gameplay wise, like you could make your meta become ranged variant such that as a havoc when you meta your meta becomes ranged, creating the most Illidan experience (but other options would be valid). Giving the spec a devouring and power at all cost vibe (maybe called devourer), such as a new essence type that drops in addition to the other essence (ripping lots of essence off and encouraged to eat it all, all the time). Empowering your demon abilities, such as meta. Granting mana burn as an upgraded disrupt (ranged and has additional effect). The new essence may even power a two layer transformation system, where you can be in the first meta tier (kaikoen / ss1) for great durations but you expend built up essence to meta tier up and temporarily boost further (beyond… lol).
Void would play a bit trickster like, almost venturing to “what if rogue was a magical ranged class” (Loki like). Warden reducing some frantic / frantic elements for strategic bursts, while reaver void would be chucking Glaives like nobodies business.
