additonal random encounters: like RDR, you have some low life approaching you begging for a little bit of gold. either response would get them to attack you (basically, like the low life in RDR when they ask you for a lift and you wait; then they throw you off the horse and jack it.) make it a little more alive and real. this isn't FO.
lastly, put in clubs and prositutes to have six with.
I definitely want the random encounters like RDR's in the game. Those were awesome and made the game world feel hyper-realistic. And the horses! My God the horses. You could see the muscles flexing when they moved. You could have entire firefights on horseback. You could hog tie people and put them on the back of your horse. There was so much detail. I loved it. RDR was almost a perfect game in my opinion.
As far as prosttutes go, I think BGS would rather leave that bit of controversy to Rockstar North with GTA. While I think it would add a bit of realism to the game, I don't think we really want that kind of negative attention drawn.
I think there should be some bounty hunter quests like in RDR. I know that this isn't RDR but with everything that's happened so far, I'm sure there are some undesirables out there that need to be hunted down and brought back to jail. Or killed and their heads brought as proof.