As someone who has spent nearly 30 years as a Foreign Service Officer, I agree with you. Zinni is not a Middle East expert. He views foreign affairs through the prism of the military, which is only one narrow perspective. Unfortunately, the CINCs have become inflated with their own self-importance and see themselves as proconsuls. The State Department has assigned political advisors (POLADS) to the CINCs to provide them with foreign affairs expertise, but their impact has largely been ineffective.
Zinni has his own personal agenda fueled by a colossal ego.
I've always found the pairing of Amb. Joseph C. Wilson IV and Gen. Wesley Clark, when he was SACEUR, especially intriguing.