Before the Celtics began their quest for banner 18, Doc Rivers stated that he wanted to simplify the playbook by cutting out about half of it. Usually when you see the Celtics run their most common sets, there is quite a bit of movement but recently there has been more confusion. When you add in a lot of direction that Rondo is screaming at one or more teammates, it has translated to a lot of time draining off the shot clock. This has all culminated in bad shots and ugly offense.
That helps to explain why their offense had been so anemic during their uneven play for the last month or so. During Game 2 against the Knicks, when the Celtics ran a simple play, they often scored and made it look easy. Below is a clip of two instances.
In the first two examples, it's literally the exact same play. The set is for Rondo to work off the ball, while Pierce brings it up. KG sets up on the right low post and Ray camps on the right baseline. Essentially, the Big 3 forming a Big Triangle. As Pierce delivers the post-entry pass to KG, he sets the screen for Ray who cuts towards Pierce. KG then passes to Ray who take one dribble to the right elbow and drills the jumper. Notice KG completely taking Ray's man (Landry Fields) out of the play, while holding off his man (Ronny Turiaf) at the same time.
In the second example, it's the exact same play, except this time Ray drills the three instead of taking a dribble to the right elbow.
In the third example, Rondo sets up on the left high post while Ray hands off to Pierce near half court. As Ray cuts towards the hoop, Pierce passes to Rondo who fakes the play by yelling at Ray to run the baseline, usually a form of the "Floppy" play. As the Knicks seemingly have it snuffed out, Pierce cuts towards Rondo who hands off the no look bounce-pass to Pierce. Pierce takes a step back jumper and drills it.
Just a couple of simple examples as to what Doc was possibly referring to.