Big fan of the Vegas series, this video looks pretty interesting. It seems there is a trend in video games to push the envelope when it comes to allowing a character to kill civilians. We see this in MW2 (and I believe its in 3, I haven't gotten that far in the single player yet). You have the option to opt out of seeing/playing that part in the game.

Bf3 has taken an opposite stance and doesn't allow you to kill civilians.

Aside from that, I loved the first Rainbow 6 game (and I loved the novel) I do miss the ability to plan out your team routes and actions.