You seem to be saying it wasn't Powell rather his staff that resisted the administration's policies. That's possible, these statements don't come from Powell, rather his "staff", Armitage. However he's Secretary of State, it's his responsibility to run the department. Something someone with military experience (and Armitage has extensive military experience as well, Annapolis grad, Viet vet and years at Defense) should be able to do. Unfortunately some of the "disagreements" with GWB pertaining to the middle east came directly from Powell's mouth. A General should know better. He did a much better job on Iraq, irrespective of his own opinions.
Now I never heard much disagreement from Powell, even ignoring the effect on the State Dept. of the vast changes Bush directed in our foreign policy- Powell had a couple of mild turf battles with Defense in post war Iraq.
You follow Israel much more closely than I do, admittedly there could have been disagreements there that I missed.