I’ve always liked the idea of having ways, in actual gameplay, to explore elements within the lore. Legion had some of this, quite a good bit depending on the class; Aluneth’s draining magic from things, warlocks being able to do certain things, etc.. I would like more things like this in the game, and I think it would be good for the lore overall, to set a precedent somewhere how a specific thing works.
On K’aresh, we dive into an arcane phase of existence and it’s a just a neat little adjacent place to explore. Now imagine if there were consequences and implications to introducing demons into it as a warlock? Your felhunter consuming things, your fel magic clashing with the world around you. As a mage, imagine if there were anomalies to siphon, or study, or do something with. Priests and devourer demon hunters could interact with the void in ways.
The coming Voidstorm is similar to this as well. So many things could be added. What if warlocks got to capture a void beast and experiment with infusing it with fel? Or mages could experiment by using arcane to probe at the void, seeking to access the prophetic powers without the risk of insanity. All kinds of things we could have, and just fun little gameplay elements that we could find and get to interact with in the world, maybe give some of us a reason to be out in the world more.