I think the Void being explored like this is more conceptually interesting to me than if it were an expansion focus, simply because I like the feeling of absolute desolation and nothingness that we've seen from the Void. That's not something an entire expansion would've been able to do, for simple reason that expansions have very base-level requirements that would've hindered that. The Void wouldn't feel like a desolate, empty hole of misery and pain if it had to accommodate an inn, two core cities with all those required vendors, multiple crafting storylines, three diverse tribal quests, and six zones' worth of unique fish.

Could some other form of content maybe have the ability to tell that story as well? Sure, I could see it done by a Eureka-style series of side-zones, and I remember when 6.1 was laying out the requirements to traverse it thinking it might be an elaborately-explained deep dungeon, or the central framework for the variant/criterion dungeons. But if they want this to be centrally important, affecting and status-quo-altering in some way, none of those can play; this is the best way to do it.