So in presently looking at the East I see One definite Contender in Miami. I see two teams that can possibly be a better team for four out of seven games against Boston in NY and Indy. Otherwise I don't see the competition for the Celtics. If we can somehow get to the playoffs healthy and stay healthy then other then Miami no one can keep us out of the finals.
You're assuming the best for the Celtics (stay at current production despite getting a year older, health..) while assuming the worst for everyone else.
Indiana, New York, and Philadelphia should all get better next year, from Indy and Philly further maturing, and NYC adding one more piece and cementing their identity after D'Antoni's departure with a full off-season.
Atlanta and Washington are both going to be dangerous teams, and are sleepers on the outside for a 'tough than you'd want' playoff series.
Paul and KG get older, so do Rondo and Avery and Green and possibly Bass and JJJ/Moore. It's probably more likely to be a benefit than a detriment.
I truly believe we saw great strides in Rajon this post season. I think he took his game to another level becoming a much better scorer without sacrificing his ability to keep others involved. I saw him take a game 7 over and will us past an opponent. I also saw him go H2H with the best player on the planet for 7 games. While Lebron was the best player on the court in the ECF Rajon Rondo was undoubtedly the second best player.
He showed greater consistency then I had ever seen him show as a franchise caliber player. I believe he transitions that to next season and becomes an ALL NBA first team pg.