I definitely think that Disney CAN be very educational and (more importantly in my opinion) very inspiring. And I think this is true of all the parks...not just Epcot and Animal Kingdom as some people have mentioned. But I think the educational opportunities are really what you choose to make of them and unless guided a little by the parents that many things will go right over kids' heads. I remember riding Spaceship earth when I was there on a trip with my high school music department and I was stunned that the ride went over everything I had been learning in my media communications class that semester.
So...at Epcot I think you have opportunities to learn about other cultures around the world of course in the World Showcase. You also can learn about energy, space travel, communication, imagination and the 5 senses, fish, the environment...the list goes on. I think that innovations can be a really neat, educational experience depending on what you do in there. There are lots of opportunities to learn more too as you exit the various rides and explore the different pavillions. True...I think many people bypass these areas and skip them but the point being that the opportunities are THERE.
Animal Kingdom is also fairly straight forward I think. You can learn about the different continents, animals, dinosaurs, and the environment. Sure there are lots of fun rides but if you take them there are lots of educational opportunities here.
Magic Kingdom I think is also very important in terms of education. While Epcot and AK focus more on science, the environment and animals I think that Magic Kingdom presents some wonderful opportunities to learn about history and literature. I mean...where do you think those rides from fantasyland come from? Sure...yeah...Disney movies...but many of those movies are based on books and literature. What a great opportunity to get your children interested in reading. Then you have the different areas themselves that I think offer great opportunities to learn about US history, the old west, the changing of the country over the decades, jungles, pirates, etc. I think the rides here in this park themselves may be less educational by themselves for the most part...but they DO present some marvelous opportunites to inspire kids to learn more about these things especially if they have parents or adults there with them to help guide them and their interests.
And Hollywood Studios again offers another sort of educational opportunity. This one is focused more on the arts...but I don't think it should be under valued because of that. The musicals, the animation, movie making, stunt shows, etc are all great opportunites for kids to learn how these things work and to inspire them. You can teach kids so much FUN stuff here...and even without a lot of direction they can just soak up so much from the atmosphere.
So...yeah...I think the parks are VERY educational. How much of that education a child soaks up depends largely on how the parents approach the vacation I think. But then...I don't think that it needs to be a boring trip either or approached in a dry, suck the fun out of Disney sort of way either. You can guide kids by encouraging them to do some of the other activites that are offered beyond just the rides, or encourage them to read books, or ask them questions about their favorite parts of rides, etc to just help take things to the next level and encourage them to THINK about what they are experiencing.
Or...you can just go and have a blast and if the kids learn something other than about spending time with family and having fun then that's just a bonus. No right or wrong way to do things when it comes to Disney (unless I suppose if you go there with no intention of having fun...that might be wrong).