Since reading Tattered Fates Ive actually been a tad bit motivated to read through other past DH adventures. This includes Maggots in the Meat.
Someone pointed out how absurd it was that the Holy Inquisition took the time and effort to notice missing dead bodies during a huge siege in a war (like a cannon ball smacking into a guard isnt going to leave a huge red stain of blood and push the body in the surrounding water!) But I was thinking of a new intro to the adventure, one that adds a bit more flavor to the setting and scenario.
Basically you remove the entire lame War of the Rhozes aspect of the adventure. Instead you boost the planet's importance by making it a wealthy mining world, but it has to be some sort of mine that the locals have little or no use for, and being a primitive/feudal planet I would say it could be promethium or a similar deposit that the Calixis Sector could mine for its use. Now by keeping the world fairly primitive it makes it easier for the merchants and miners to get away with stealing (or paying little for) the fuel.
However, you keep some of the background and myths in the setting. The cult and monsters mentioned on the rumours table. So the imperium keeps a decent eye on the vast supply of fuel. When a series of grueling murders and dissappearances take place in the floating city, accusations and rumours fly that the royal family there is in league with an ancient cult or monsters or demons. So the rival power seeks to keep the taint from reaching the mines and thus blockades the town. It isnt really a civil war, just an attempt to keep the evil in the heretical city.
The Inquisition notifies the Acolytes to investigate the rumours of cults and monsters before the siege even begins.