The JET thing is a little excusable because of the guard problems we've had, what with Lee playing like garbage (offensively), and Bradley being out. Now that AB is back and Lee found his mojo, perhaps JET will be able to lead the bench like he was supposed to, and we'll see more variety. He shouldn't be on the floor at the same time as Rondo, imo, which is what causes those endless screens.
Remember that Ainge picked up Terry partly as a response to Doc's request that he be given some personnel that could create. Last year we just had Rondo and Pierce. This year we have Rondo, Pierce, JET, Green, Barbosa, maybe Lee as well. So you have to believe that Doc was just waiting for the right pieces to come together.