haha great one Quagmire on the Marbury thing :-) (no I defnitely don't want him to the Lakers)
personally I think their problem is their attitude, and it all started with KG, the way they confront their teammate is probably not the best way. As anyone involved in sports'd know it's all about momentum, when you've been shouted (or even pushed around) by your teammate the team can breakdown quick.
And also, Lakers last month when they beat the Celtics they kind of showed the rest of the league a different way to defend against Celtics and Celtics just doesn't seem to have found a way to counter it yet.
As much as I hate to say it but I think they'll regroup and start get back to form just before All Star break and carry the momentum through rest of the way.