I think we would have a very large disagreement on what free will is. I call what people commonly refer to as "free will" volition. Most acts that I do on the day to day and even most thoughts I have are not of my choosing. Most people are on auto-pilot much of the time. It takes a severe amount of discipline to remain truly aware and volitive for the majority of one's time. This is, indeed, what a lot of meditation is all about. Gaining and remaining in control, to remain mindful and aware of one's self, one's thoughts, one's emotions, and in turn one's actions. For those who suffer something like an impulsive disorder or borderline disorder, meditation is actually the main treatment prescribed for this reason.

I suppose what I am saying is that most of the time most people do not have "free will" if you mean that "free will" is some magical thing that makes people completely non-deterministic. The thing is, that doesn't matter. The illusion of free-will is so good it is largely irrelevant that it doesn't exist. As for whether or not we can overcome our own minds, I believe that we can. As to whether or not external stimuli and mind-control are good ideas: absolutely not. Even if they might help those who suffer, those same tools will be used by tyrants all over the world. Imagine what the CIA or KGB would do with that sort of technology.