When Blizzard entirely ditch the decrepit cast and tell the story their current writers actually want to tell, which is the cosmic one, they abruptly can make it pretty interesting. Sure, it takes more stitching than is humanly possible to make it work with what we've seen before and would still tear at the seams, but by itself it's fun, which counts for a lot.
Also while I think the evidence for this isn't 100 set thus far and I don't know if I'd even like it, the idea that those Dreadlords that Sarg interrogated were working for the Jailor and were meant to push him off the edge so he could get the Titans off the board and then aim him at the Light and Void as well is a pretty good call given page 3. The comment about Life also reframes the whispers in 8.3 and the bit about cunning ones now doesn't mean themselves or opportunism, but a specific group tied with Death. I wouldn't be surprised if the writer was Denathrius from back when he was a Dreadlord.
I'll also put it out there now that the reason the Jailor was banished was for getting involved in the cosmic tug of war. You'll notice that even Maldraxxus is reactive - it fights against invasions and collects information to prepare for them, but it doesn't seize territory or go after souls it wouldn't normally have, and all the other 'main' covenants just manage their own affairs. The Kyrians are so appalled by the concept of doing literally anything outside of their insular scheme that it's why Devos turns on them. Whoever Zovaal was and whatever the Maw used to be, I expect him to have tried to expand the power of Death over the other powers and betrayed the other Shadowlands groups by robbing of them of their anima and doubling up on their functions (making his own army and his own psychopomps) to do it, resulting in his banishment. Hence him taking the slow, subversive route like this.
Edit: Writing like this to keep my thoughts as they were, but I think we might be jumping a bit in giving credit to the Jailor. The recipient is likely Denathrius himself and the writer one of his specifically sired creations, creations that I'd bet turn into dreadlords when exposed to fel. Denathrius is called 'The Master' after all, and he sounds a lot more like someone who'd care about flattery in address than the Jailor. Hell, it flat out says that the people the document writes about were 'sired' for this task. The quote also sounds like it's from Denathrius. Do you see the blue man talking about desires?
This'd also change that last part because then Revendreth would be involved in conspiracies outside of their domain.