Well if you're judging his impact based off of his on court/off court stats, he's clearly made a difference in the past two years...
On: .502 eFG% 20.3ORB% 68.6AST% 15.3TOV% 104.4Ortg
Off: .484 eFG% 18.8ORB% 62.7AST% 18.3TOV% 96.7Ortg +7.7
On: .476 eFG% 20.5ORB% 59AST% 14.2TOV% 102.2Ortg
Off: .428 eFG% 18ORB% 56AST% 16.8TOV% 92.3Ortg +9.9
On: .537 eFG% 67.1AST% 15.7TOV% 110.1Ortg
Off: .487 eFG% 56.3AST% 17TOV% 100.8Ortg +9.3
On: .533 eFG% 24.9ORB% 61.6 AST% 109.7Ortg
Off: .441 eFG% 19.2ORB% 45.8 AST% 92.1Ortg +17.6
So in over 5600 minutes where Rondo was on the court versus the 2800 where he was off of it, the Celtics shot the ball at a higher percentage, were a better offensive rebounding team, assited the ball at a higher rate, turned the ball over less, and produced more points than their opponent.
It hasn't been true much this season, mostly due to his play over the last month, but it's clear that we are a better team with Rondo on the court. It seems silly to even debate this...
Hang on a second - all the numbers you are showing here are offensive numbers.
Rondo has a positive offensive impact on the team this season, we all know that. Even the numbers I quoted showed that.
Our offensive rating is +2 (which is good) when Rondo is on the court. However, our defensive rating is +4 (bad) when Rondo is on the court. So we score 2 more points, but we allow 4 more points. Net result is we are losing by 2.
Also I'm not so concerned about his on/off rating for the last two seasons, I'm concerned about this season.
To me it seems the instant Pierce declared Rondo the new leader of the team, that seems to be when things got to his head and he turned especially cocky and arrogant.
So other stats suggest that we do tend to win more when Rondo has big games. That suggests the following:
1. When Rondo plays great, we tend to win
2. When Rondo plays lazy, we are better off without him
Since our overall will record is better without him, this may suggests that he plays lazy too often for his own good.
I'd love to see what our record is with/without KG and with/without Pierce since 2008. Not sure if anybody can pull those stats up, but I'm pretty confident will will have a major drop off in win percentage.