I disagree that the team plays better without Rondo. He clearly makes us a better side.
However, he has had the luxury of playing with a crop of excellent jumpshooters for pretty much his entire career.
Bass and KG have been in the top 3 to 5 jump shooters in the NBA for quite some time now at the power forward position. They've both been number 1. It's true that their spacing helps Rondo- but it's also Rondo's pinpoint passing that assists them to an extent as well. They need each other essentially.
Pierce is much the same at the small forward position as a jumpshooter. I won't begin to talk about Ray Allen.
Bottom line is that Rondo makes pretty much any team he plays on a better team. If he's hot and hitting his jumpshots and threes AND surrounded by excellent shooters like we had from 2008- 2013 then it's hard to fathom that we still lost to Miami.(brag...I went to most of those ECF games in Boston and Miami and I still shake my head thinking about how lucky Miami were).
The good news for us is that he's worked on his shooting while he's been out with the injury. He's also bulked up around his upper body/torso which has presumably helped his shot but also given him the ability to take contact around the basket more which he knew he'd need if he was going to become a more consistent scorer.
His assists may go down slightly due to lack of talent around him
on the whole, but his scoring should go up given his improved strength and shooting technique.
At the end of the day you may like the way the C's play without Rondo but you're 1000% crazy if you think they play better without him.