I don't think someone would need to be a master of both languages to greatly improve the way it's taught. For instance, one of the problems is that characters tend to be taught to foreigners in a completely bizarre manner; you end up learning many compound characters before you learn the component parts. Other issues include the small amount of Chinese in the course (lots of speaking in English about Chinese), the focus on things like grammar, and the idea that Chinese is so difficult that poor results are acceptable.

I've seen a number of people with a low-level in Chinese develop self-study plans that were much, much more effective than class or text book I've seen.