Voidwalker is a very strange subclass because it performs far better than the sum of its parts. The Melee is awful, the Supers are lacklustre and, as you say, one of its Aspects faces competition from a Fragment that is available to everyone. Yet, somehow it is still very good. Instant activation of Devour was meant to be a feature of Secant Filaments, but if you're making a Voidwalker Rift build then they're thoroughly outperformed by the new Briarbinds. If Feed the Void was reworked, I'd love to see it incorporate Suppression somehow, as it's a very strong but criminally underused keyword.