Having thought a bit about the social system, it's actually a pretty clever mini game combining actual social roleplay and game mechanics. As I read it, all NPCs have a disposition starting from 40-60 based on mood, modified if they hate or love the inquisition and recognize that you're in it. You have five social "combat" skills: charm, intimidate, deceive, observe, and command. Each NPC gets a little social stat block giving his personality, and which social effects work better or worse on him. You can figure out what might work through roleplay or observing him. Whenever the NPCs try to get something out of the NPC you roll on the disposition, which goes up or down from using the other social actions against him. I think that this section is actually quite ingenious and probably deserves to be fleshed out a bit and organized into a full fledged social combat section.
I think it deserves to be mentioned that this system doesn't need to be used for every social encounter, but why not throw it in? If combat gets to be a granular thing, I don't see why social combat shouldn't be as well.
Honestly, I feel like social combat and the rules on subtlety should get their own chapter and fleshed out a bit more so that the PLAYERS read about them and not just the GM. I've seen almost no threads commenting on these, because they're buried in the GM chapters and don't get 2 full chapters like combat/weapons do.
I know a lot of people rarely used the pretty awesome Endeavour system from Rogue Trader (for a lot of reasons) but I hope this social system doesn't see the same fate. I think a big help on that front would be for the core book to more explicitly support and require its use, same thing for the influence system, and the investigation/clues system.
What does everyone else think? What could be done to cement these mechanics in the game to the same extent as combat?