AMC's Mad Men Season 4 finale

This finale didn't quite have the bang last year's did. I was a little disturbed that Burt Cooper quit the agency and no one took it seriously. Are they really getting rid of Robert Morse just like that? Then again, they did dump Sal (Bryan Batt) and Kinsey (Michael Gladis) rather unceremoniously last season. Meanwhile Don's engaged, Peggy's proved herself once more, Joanie is still carrying Roger's baby but will pretend it's her husband's, Betty's still a bad mother, and Pete had his portfolio saved by Don. That final look out the window by Don... does that mean when we pick up next season, he'll already be thinking of cheating on his new wife?