I'm not saying be a running team, but to puish the pace and Rondo has done it well versus that type of defense on many occassions. If Rondo doesn't walk the ball up the court, allow the defense to get set and initiates the offense with 20 seconds or more on the clock, then it's difficult for that defense to employee the type of defense they want to. It doesn't have to be fast break, just a faster pace. When Rondo walks the ball up the court and players get to their assigned positions on the play and the play starts at the 16 seconds left on the clock mark, then the Celtics play right into the opposing teams hands.
Second, just because teams sag off Rondo and packs it in inside, doesn't mean that the Celtics running their offense and running plays that set up outside shots won't work. And if they work and those outside shots start to fall, then eventually that type of defense will need to adjust to come out to defend the outside shooter and will open things for Rondo to drive and dish.
A Ray Allen play running around double screens and hitting a corner three, the 1-3 high post switch with Pierce, the 1-4 high post pick and pop, and several other plays will and can be very effective against this type of defense and if KG, Pierce and Allen are hitting that outside shot, the defense will expand openiong up Perk down low and lanes for Pierce and Rondo to drive and for KG's alley oop play.
Sagging off Rondo doesn't necessarily always make it more difficult for the rest of the team's offense. As long as the offense pushes the pace and then runs the plays instead of Rondo ground pounding the ball looking for something then at the last second tries to find someone, the Celtics will be fine.
And of course I know that the OP is talking about that it's important for Rondo to be able to hit that shot. All I'm saying is that if the Celtics run the offense and the best option after running it is that Rondo shot then another way of stopping that offense is for Rondo to hit that shot a few times early on. Once he does, that defense will adjust. But that is the least likely and effective way to break that defense because Rondo's shot is the weakest part of the Celtics' offense.
I don't think he's stubborn about it, just that he knows, like the defense does that he shouldn't be taking that shot if the Celtics truly want to be successful. At least this year anyway.