My main hope for the Lathes Worlds is to see further development of Belacane, one of the minor forge worlds in the Calixis Sector.
Back in the day, Black Industries opened up the Calixis Sector for fans to write in with suggestions for individual worlds. I got in there fast with Reth and Belacane, and my write up formed the basis of the sector guide to both of these worlds. Ever since then, I've kind of thought of these worlds as "my" worlds. (This feeling is, of course, totally irrational - I recognise that they're not "my" worlds in any sense at all!)
I wrote up Belacane very much in the spirit of 5th ed. 40k, which introduced the "five minutes to midnight" feel of the failing Imperium. 5th ed, mentioned that the Golden Throne was failing, so I deliberately linked the Calixis Sector to that by making Belacane a centre for the production of Stasis fields… except that the Belacane Magi have lost the knowledge of how to manufacture them, and are desperately trying to cover this up to maintain their power and prestige.
My thinking was that Belacane was a microcosm for the failing Imperium - one of a number of key worlds whose knowledge was useful for keeping everything (especially the Golden Throne, which I reasoned would need some stasis tech) ticking over, and that for reasons of pride, the world's rulers are actually concealing information that the Imperium desperately needs to know.
I also gave a nod to the "Wizard of Oz" with the prideful Belacane Magi engaging in increasingly shameful and pathetic attempts to pretend that the most famous, ancient and powerful of their order is still alive.
It was really nice when Rogue Trader explicitly gave a shout out to my interpretation of Belacane when it talked about how Rogue Traders use the world's stasis vaults to store their warrants of trade and banners. There was also recent coverage of the world in an ocean-stealing scenario in (I think) the Book of Judgement, though the treatment of the forge world there was a bit more generic.
My main hope therefore for the Lathe Worlds is that Belacane gets some more love, and that we see more about its rulers' desperate attempts to conceal their own ignorance and maybe some interesting new stasis tech!