I'd like to counter the notion that Rondo isn't that good of a defender/ rebounder.
Ummm, yes he is. Someone pointed out players average a PER of 18.0 against him vs. the league-wide average of 15.0. First off, everyone and their mothers know that PER is skewed in favor of those who contribute in limited minutes (cough cough Wright cough). A more accurate measure is DPRM which takes into account points allowed per 100 possessions. Rondo is 4th in the league.
http://espn.go.com/nba/statistics/rp...RPM/position/1
Rondo also leads the Celtics in defensive +/-, not taking into account Gerald Wallace who plays 8 mpg.
http://www.basketball-reference.com/teams/BOS/2015.html
Rondo is also 1st among PG's in defensive rebound % & 6th in offensive rebound %. To top it off he also leads the league is assist ratio (% of possessions that result in an assists), and assists.
On offense, Rondo's struggles seem to be overstated. He isn't shooting well but he's running a relatively efficient offense considering their roster. The Celtics are 6th in PPG, tied for 11th/12th in FG% at .461 (the immediate 3 squads ahead of them are at .462). They struggle making and defending 3s and turning the ball over.