I'm not a big fan of the 40K universe either. It's a bit too dark for my tastes. I picked up the "Rogue Trader" rules not that long ago, and I liked the system, but the setting and all the background material was just so darn depressing.
Here's what I'm thinking for the Sci-Fi game: Humanity, who had spanned the galaxy suffered a massive catastrophe when a technology they relied upon failed suddenly. Sectors and worlds got cut off and had to both fend for themselves, and re-invent everything they could previously do. Game starts just as interstellar flight is coming into its own again.
Players take on the role of spies and agents for a particular planet. Smaller in population than its neighbors, and unable to support a substantial military, the agency is tasked with keeping the much larger neighbors at bay, and looking out for the planets interests in interstellar politics. Players would go up against the intelligence arms of the neighboring inhabited planets in various espionage and heist style missions. With each new mission, players would have to choose between several options of where to spend their resources, i.e. extract an asset who's cover was recently blown, thwart a suspected terrorist bombing plot, or raid an enemy sleeper cell.
I'm thinking I'd like my players to run two characters, a senior level official who decides with the others where to send their assets, and an asset itself who'd be a member on an elite squad of agents along with the other PCs characters. The senior officials would likely be mostly stat-less and there for the RP, and the agents there for the action sequences.
I'm still trying to decide on what system to use. Stars Without Number has some great tools to run this sort of game, and the rules system itself is simple to grasp, and free to download, meaning that there's a low barrier of entry. Or a mashup of the espionage GM tools from SWN and GURPS characters.
Grigory:
This is quite a bit like the setting creation I've seen in a few different flavours of Fate. It's worked out really well when I've done it in IRL :)
Good to know, thanks. I've been playing Dungeon World lately in face-to-face games and it leaves a lot of setting creation up to player actions too. I've enjoyed the mechanic. How do you like Fate? something about the unique dice just kinda irks me.