Last night I picked up the new issue of Xbox 360 World magazine and there was a very detailed article about SCC. It included some new info on various parts of the game.
SINGLE PLAYER- From the sound of the article the game features both daylight and night time levels. However for at least the majority of the game social stealth will be your primary means of staying hidden. Also, the game is broken down into 60 levels of 15 minutes a piece. This works out to 15 hours of gameplay!!!! The first twleve episodes are spent working with 3E. These levels will be more "Constrained" than the later levels, teaching you the lay of the land and the new control scheme.
The H2H combat system is also very complex. What moves Sam uses are based on range and position of the opponent as well as proximity to any "weapons". In other words if there is a door between Sam and the baddie, Sam may hit the guy in the throat and then smash the door on fis face. Previous SC games contained only 2-3,000 animations. Conviction already contains over 10,000. They also said that the Holiday release date is actually a bit ambitious. So dont be surprised if its pushed back.
COOP- There will indeed be Coop mode in Conviction. It will NOT just be the addition of another player to the SP mode. It will be a separate mode. other than that details are scarce.
MULTIPLAYER- And I quote, "On Live, Players look like any other members of the crowd and compete for objectives while trying to sabotage their opponents".