I think you're most certainly on the right track with this train of thought. This patch has done quite a lot to show that while usually tending toward the good, the Light can go too far and be wrong. There are of course examples of this in other places in the game and Lore, but this hammers it home even more. Now we're seeing that the Shadow/Void, while tending toward the negative, can be used for good if handled in a very delicate and careful way. Alleria is doing something that we haven't really seen before in consuming the hearts of Void revenants and dark naaru, and that's something that's setting her apart as a major named Lore character. But the point this week's content has striven to make is that the Shadow/Void can actually be used without devolving into total Void Lord/Old God manipulation and insanity. And we have examples of that in the game and have for years. Obviously shadow priests are the first things that come to mind. They get dangerously close to the Void Lords/Old Gods, but they somehow still keep a shred of themselves intact. Warlocks, specifically affliction locks, have been dabbling in the Shadow in a more caster-y sense while keeping their distance from the mind melting of the malevolent entities that live within the Void. And while not everyone loves agreeing with this one, rogues, particularly sub rogues, have been dabbling in the Shadow in a more physically-enhancing way in the same fashion.
This patch has really done a lot to clarify some things about the Light and the Shadow that at the same time help to justify a lot of the choices player characters have had for some time. What Alleria is going through in learning how to use the Void without losing herself to it isn't something that's a foreign concept to the universe. It's just her own journey to arrive at a very similar destination, albeit in a slightly more extreme, Void-eating sort of way.