A couple comments.
I'm hesitant to really consider Waldorf "developmental." Yes, it's playbased but there is a belief within the Waldorf community that it's "wrong" for young children to have academic pursuits even if it's developmentally appropriate for them. A developmental preschool is supposed to allow for the diverse interests of it's students. There should be writing stations where 3-year-old could scribble pretending to write a letter but also be appropriate for a 3-year-old who could actually write a proper card to grandma. Montessori is developmental in theory but you have to be really careful when choosing a school. There is more money in
I think you're reading too much into the "developmental" label. I think it just means "we're not particularly concerned with explicitly teaching academic skills." I don't think it describes any particular philosophy or approach. Except that due to the absence of academic teaching, it is likely to feature a fair bit of social, physical, imaginative and creative play.
Miranda in rural BC, Canadamom to three great kids and one great grown-upunschooler, violist, runner, doc