Along the same lines as the Page Level Permissions, I would like to see a few things added to Sites that I believe would make it better for far more than simply education.
It would be nice to be able to create users within a site, apart from creating full Google accounts, so they can access information specific to them, and not modify anything.
With privacy being such a concern these days, especially in the realm of Special Education, adding a "Sign In" type page would be ideal. Depending on the username and password entered, it would respond by linking to specific information, a page specific to them containing personalized information. This could be great to have students show ePortfolio's without creating another site, and sharing information with parents, as they would simply log on. Currently, the only way that this could be done that I can figure out is to have links accessible and only allow access to certain people. The problem with that is students are aware of the links, so the information contained has to be somewhat concealed or private.