This slump has lasted too long to wait it out, and hope that the team and the current rotations fix things. Doc has to mix things up, perhaps radically, to see if something else will work better. This is what I would do:
1. Insert Patrick O'Bryant in the starting lineup, and bring Perk in off the bench. O'Bryant played very well with KG on the floor (there were a few articles on this in during the pre-season) and playing with the big 3 would take some pressure of POB and probably leave him with some scoring opportunities. I am not being critical of Perk on this. This would enable Perk to be used more in the second unit, and provide it with a true big guy who is experienced. O'Bryant would struggle more in the second unit. By playing with the big 3, he could prosper.
2. Replace Rondo in the starting unit with Pruitt. Let Pruitt play the PG. See how he handles it. We lose some of Rondo's penetration among the starters, but we gain another very good outside shooter in Pruitt. I think Pruitt can penetrate pretty well, and his outside shooting is a bonus, and would make it more difficult for teams to double off of him than they do with Rondo. Pruitt's defense is about as good as Rondo's, in some ways better in my opinion, in that he takes fewer chances and has a little more size. The added bonus is bringing Rondo in off the bench. He could be a great spark plug for the second unit. He could create a more consistent running tempo with the second unit than with the first, because it is much younger and faster. I still love Rondo, but I think this little shakeup might be what is needed for him. He could still finish games with the starters (so could Perk for that matter). I just think this would enable us to stretch our lineup better.
3. Bring up the rookies, one at a time, perhaps, and give them some burn in the second unit. Give Giddens some of TA's minutes, and see how he handles them. Ditto Walker. Playing alongside Rondo and Perk, I think there is a potential combination that could work well.
4. I would play BBD over Powe right now, especially if Perk is moved to the second unit, as BBD can go outside a bit, while Leon and Perk play the same spot on the floor. I think BBD is playing with more energy than Powe of late. Powe seems to have gotten very frustrated on offense of late. I like Leon, and admire him greatly for what he has done so far with his career. But the shortcomings of his size in the PF position are becoming more and more glaring, especially since he has absolutely no outside game. Scal can also substitute in here depending on the matchups.
5. Eddie would be the back up 2 guard. We could not bench him in this scenario because we need his outside shooting. Of course RA could spell him after 6 minutes or so.
This would be an experiment, of perhaps 2-3 weeks, to see if it can help kick start us out of this slump. If it works, great, if not, then at least we are trying. Repeating the same rotation that no longer seems to work, even against mediocre opponents, is, to paraphrase Einstein (I believe), the definition of insanity.