To put it briefly, Miller falls into the standard "let's fix the governance structure" fallacy of a certain chunk of education reform wannabes. I just don't buy it. If school-board parochialism were the main problem, then we'd find Hawa'i's schools outdoing the rest of the country because of its unitary system. Or we'd find Southern states outdoing the north because many of them have mostly county systems, in contrast to Northern and Western states with tiny, fragmentary districts. Or New York City's system would be perfect today because of the elimination of the elected school boards through mayoral control. I'm sure that there are governance changes that would matter, but this one? It's bold, provocative, simple, and not very helpful.
This is the same obvious analysis one should make about the "First, Kill All the Teachers' Unions" argument.
Also, Miller's argument seems to be based on the idea that only a set of special interest groups like local control and board governance. I think the support is much broader and deeply-rooted than that.