I agree the offense has gotten too static (although I thought it was much better game 3 of this series), but the problem is that the Pistons are daring Rondo to shoot open jumpers and he's not doing so. He needs to take those open shots, or they need to take him out, because if he's not shooting the open looks it basically allows Detroit to play 5 on 4 defense.
No, that's not really the problem. That's what the announcers on ESPN have said over and over and that's probably why you believe it. For some reason, they have been reluctant to criticize the "new big 3" as well.
Rondo has been hitting those jumpers fairly consistently throughout the playoffs - as he did throughout the year, but it's actually besides the point. The C's are sticking him over on the weakside and by the time the ball gets to him, a Pistons player has rotated over, so in fact, they are not "daring him to shoot" as Van Gundy has probably erroneously said 50 times this postseason. They are leaving him open to double the ball as they would any other man on the weakside. Their defensive approach doesn't change with Eddie House or Cassell or anybody else in there, nor would it. The C's often employ the same aggressive defense as well, and they do regardless of how good the Pistons can shoot, and the Pistons do have 5 good outside shooters on the floor with their starting 5.
The problem is that the Celtics are not passing the ball enough. The ball goes to KG or Pierce on the wing, and the offense stops there. They need to move the ball regardless of whether someone coming off a screen has a wide open look or not, you have to run the offense, you can't just be static. Ball movement will create open shots, not mismatches.
The only clear offensive mismatch the C's have is Rondo's speed is better than Billups, injured or healthy, and they aren't taking advantage of that b/c, as I said, they are just dumping the ball to KG/Pierce on the wing and moving Rondo to the weakside. Doc knows better than this, and so do Pierce and KG - I don't know how they went 48 minutes last nite with the same crappy offensive game plan and execution.