I am glad you are working on a curriculum. I understand that there are some (many?) from the PC community who will not want/need such a curriculum for their kids, but I think there will be a large enough market (particularly of those new to permaculture, of which there are more every year) who will.
My own two kids are in an alternative public-school program, where they are homeschooled 3-4 days a week and go to classes run by the school district 1-2 days a week. Since I have been part of this program for 5 years, I also volunteer as an advisor to parents new to schooling their children at home. For most of them, if a subject is not in a curriculum, the parents are not interested. They are too overwhelmed and too busy to grasp pulling something together on their own. I have also attended several at-PC-conference-roundtables about PC/education/children. The thing that has struck me over and over again is that no one really knows how to teach PC to kids in an ordered/understandable way that also engages the kids. I think there will always be those people who need an open-and-go book to guide their attempts. So I definitely think there is room for both the curriculum approach as well as the more organic/create-your-own approach.
My main question/concern about a curriculum is how one makes it engaging and meaningful to kids, versus just more words on a page that they don't really grasp and don't really have meaning for them (like too many textbooks that exist already). I think that will be the key to either success or failure in a curriculum. You may want to take a look at Tom Elpel's book Shanleya's Quest, as well as the SQ cards & games. I think he did a fabulous job of teaching kids about 8 common plant families with those materials, in a way that is creative & "in-a-book-but-not-textbooky".
I have some other thoughts but am out of time right now. Will post more later.