This has been on my mind as well -- my oldest child has just become a bookworm and I'm intending to get all my kids iPads this year if they can be more than just for games and movies.
While strong AI would be nice, well crafted content alone could take one very far. Then add in what Khan Academy is doing for tracking learning and you might be 90% there.
Kindles (the eInk ones, not the Fire) might be a good push in the "for reading" direction. You really can't do much else with them, but they're really great for reading, as well as super light, and have amazing battery life.
I got a Kindle Fire, and reading on it is just not the same as with the 'real' Kindles - you always have 'other things' like email and Facebook lurking just a few clicks away. And the battery life is something you have to keep in mind, and of course an LCD screen just isn't as nice for reading.
While strong AI would be nice, well crafted content alone could take one very far. Then add in what Khan Academy is doing for tracking learning and you might be 90% there.