Stats are great but have to be taken in context.
1. Rondo has hardly played with the best defensive player in the league this year. When Avery Bradley was added to last year's starting team, they became the best defensive team since the 2007-08 Celtics. Bradley was not playing with Rondo for most of that pre-injury record. Bradley might be playing his best ball as a Celtic right now.
2. People mention movement when they mention the difference in the offense pre- and post Rondo's injury. Think about that for a moment. If players were getting off on fast breaks with Rondo and moving around more in the half court when Rondo was around, do you think the Celtics record would have been what it was prior to his injury?
3. The Celtics have had starts of seasons when they are unbeatable and they have had starts when they sputtered along until something clicked in they play great. With Pierce and Terry fighting through nagging injuries, with no Bradley, with Green and Wilcox overcoming heart surgery operations and with Lee, Green, Terry, Barbosa, Wilcox, Darko, and the rookies all trying to figure out their roles, this wasn't going to be a year where they started off unbeatable.
Yes, I think a definite line of demarcation can be drawn around the time Rondo got injured(though I think around Bradley's return would be better) where this team's performance changed and several players suddenly saw the quality of their effort, their performance, and their knowledge of what they were doing increase and make the team as a whole play like the contender everyone thought it was going to be before the season started.
Unfortunately regular season wins and winning 4 games out of seven games to the same team as they game plan your players much more individually are two different things. We couldn't beat Miami without Bradley last year, We certainly aren't beating them without Rondo, Sully and Barbosa.