I wish more people would grok the basic principles of Montessori and just focus on doing those right - because when it's done well its perfect and really doesn't take much structure. My wife runs a Montessori school from our home and has been a teacher for almost 12 years now. She has found that the more hands on she is (and other teachers are) with the students, the worse the outcomes are. As practitioners we see a lot of junk that claims to be "Montessori" but doesn't really stick to the principles. These are primarily: self directed learning and building a community for exploration and creativity.
The best Montessori schools have agreements with local warehouses/mills/shops etc... where children can do internships and apprenticeships. Having "curricula" like the article states is generally antithetical to that and kills a large portion of what makes Montessori so successful - which is pupils taking prepared "vocational" paths which are liberal in educational scope. It's simpler in the long run but takes much more up-front work and I think the technology is there to make that up-front work much easier.
The real challenge is fitting these types of schools into the larger "schooling" world of standardized tests etc... One thing we found was that many students leave Montessori because the clearest path into college is through the testing system and Monetssori doesn't play well with that. That is what needs real reform.