So, here's a couple
easy ideas for narrative hooks, that will swiftly go off the rails into fantasy land.
-Names. NAMES. Cultist rebellions should be led by leaders with generated names so we can put a name to the severed head we offer up to the Emperor as proof of our service. This is already happening in a lot of places (Space Hulks and Faction Leaders, the principals in some Inquisition missions get names) but more could be done. Minor threats could get named (it'd be amazing to have our purges recorded 40k style, like the "Purge of Boatmurdered" or "The Abraxian Cleansing." Incursions and invasions could be handled the same.) Planetary governors could/should get names. Shit. Go crazy. Generate names for enemy forces too. That could open up doors I want to, but am not going to, speculate on.
-As mentioned, extending the life of some quests with additional objectives would help. For example, if you need to drop off a 'Gaunt sample to the Inquisition, and that planet happens to be under assault by another enemy....
-Distress calls and a fog of war. Right now the game just tells you there's the appearance of enemies. If planets could accurately assess whether or not they're going to defeat the enemy forces on their planet, and send out distress signals, those would give both purpose and flavor to the core of gameplay: flying around and picking fights. Planets with over 50 million soldiers don't really need the Astartes' help to fend off a moderate Ork threat. It might even add to the game's difficulty if you suppress some notifications, unless a unit is X jumps away. Maybe make the success or failure of these alert posts semi-random, to reflect the occult and unpredictable results of Astropathic communication. Non-random variables might be the event (invasion, capturing a planet, warpstorm, major vs. minor uprisings, event type like a Space Hulk appearance vs. WAAAGGGH. The difference between Astropathic communication and rumor, really.) Maybe that's starting to tread too deeply into unclear gameplay/difficult programming and UI issues. But I think being able to glimpse the larger picture of the state of the Imperium in some ways hurts my late game enjoyment. I've seen it all and burnt out and am just waiting for the next crisis to leap on. I guess what I'm ultimately wanting here is a fog of war in and a cooler/fluffier way to get information about what's going on in the galaxy. Maybe we need an Astropathic Choir tab.
Everyone has to have them to communicate across space, after all. You could make that the Chapter Log tab, is the Astropathic Choir tab.
-A better sense of when factions are going to war with each other. Fights between AIs are unseen in my games so far, since they're usually not in control of shit in my galaxies. Imperial factions should also be capable of going to war with each other too. I know I'd enjoy watching the Inquisition giving those smug bastards in the Mechanicus exactly what they deserve. Hell, I'd help, if the cause was righteous in the eyes of the Emperor. It could make for some amazing fleet battles and stories if a Xenos or Heretic decides to get in on the action too....
-More faction corruption. Right now cults rise up and get crushed, fleets show up and get blowed up. It's be nice if a Mechanicus or Imperial world could rapidly fall to Chaos and full on convert, creating a new, potent, dug-in enemy to face. This would need to be pretty rare so it doesn't completely overshadow regular old cultist uprisings. But I feel like the cultist uprisings seriously lack teeth.
On the more content/feature-heavy side of things...
-Game events, or at least game-wide wars. Wars other than Tyranid fleets seem to start very small. A planet or two at a time. If you got a real incursion, I'd expect two or three systems, all planets, to fall under control of the enemy. Of course, that'd have to be carefully balanced so it doesn't like, surround a chapter world or kick a starting player while they're down. But it would carry forward the momentum of the game that seems to peter out once you eliminate all the spawned enemies on the map.
-I feel like interacting planets could be more meaningful. I know the work is started here with planetary approval values and reclaiming them, but again, more could probably be done. It'd be nice to spend more than 1 turn interacting with planetary features, for example, or give our marines longer-term duty assignments (like patrolling a world cleansed of the Ork menace, to clean up loose ends and ensure they're not repopulating.) Maybe recovering STCs and other cool shit should take more time than it currently does, and tie up your forces for longer. And if something were to happen to that planet while they're on their long duty assignments......you start getting the beginnings of a narrative. Or for example, there's lots of generic adventure that could be had on Feral and Death Worlds. Maybe players should be able to explore planets repeatedly, and while there'd still be notable sites like now with their one-shot results, maybe exploring generates random events which can have long term consequences. Like, exploring a Feral world you discover a previously unknown clutch of orks and that touches off an invasion. Maybe you're mucking around on a death world and lose random numbers of marines to carnivorous planets and shit. Maybe you find a valuable resource which gives you a trickle of requisition for a while, as long as the Imperium retains control of the planet. Maybe you come across an old Chaos site and your Librarians go mad, or some of your marines are secretly corrupted.
In fact, I think not immediately revealing some sites and requiring your marines to scour the planet would be a great change. Because right now there's three kinds of planets: planets with artifacts and sites to discover, that I know about right from game start. Planets controlled by the enemy. And planets I don't give a shit about for the most part. Recruiting maybe, tribute maybe, but there's tons of systems I only care about in the context of Heresy. If every planet potentially had a site that I would have to assign marines to search for, in addition to what we already have going. That'd be great. STCs could be made rarer not just by dint of the RNG, but by how much effort and manpower it takes to find them. Of course, while many large features would be spotted by Augurs and Auspex scans from orbit, not all necessarily would. Some sites you wouldn't have to search for, like Sororitas Cathedrals. But I think ruins could easily be hidden. (Or you create multiple kinds of ruins. Big ruins with more content that are easily/immediately found, and smaller ruins with smaller content that you have to search for.)