I don't think many kids are going to be using their raspberry pi to redesign the CPU or rewrite the firmware drivers.

The idea should be to make programming simple and accessible, perhaps being able to create some games or connect it to an arduino and make some fun toys.

I actually think that shipping it without a box is great idea, it demystifies computers a lot if you can see that it all just boils down to a bunch of wires and chips on a PCB. Making a custom case could also be a great Design/Technology class project.

Is it a perfect open platform? No. Is it a lot more open and inherently tinker able than a locked down Windows 8 PC or an iPad? Hell yes.