It’s a huge change, and I don’t think anyone could confidently predict just how it would alter the education landscape. However, my guess is that a comprehensive voucher system would effectively mean privatizing education, albeit with massive government subsidies and presumably some functions still being performed by the states directly. I don’t think that’s a bad thing.
Like almost everyone else, I’d be perfectly satisfied with fixing public schools rather than switching to voucherized private schools. The problem is that it seems as if public schools are ill-equipped to address their deficiencies in a timely and efficient manner, largely for reasons that would be much less of a factor in the free market: little incentive to innovate and improve, no effective mechanism for change, and the hindrance of static rules handed down from centralized bureaucracies.
I don’t see it as “passing the buck” to the free market. We compose the free market every bit as much as we compose the government, therefore public education is just as much a passing of the buck to the government as private education is the opposite. Either way, it’s a question of deciding on the proper venue for education, not of abrogating our responsibilities.
That’s definitely a problem, but the severity of that problem is up for debate. IMO, it would be unwise to sacrifice generations superior schooling because of an aversion to a few years of increased confusion and uncertainty. Besides, if the change to a voucher system were incremental (as it would pretty much have to be) the panic should be kept to a (relative) minimum.