What I would like is the book to become the academic environment. I suppose that's a bit far off though, I mean how long have we been reading about the virtual classroom,
But as an example, let's imagine the future of the cookbook. There are countless cooking ebooks available, most of them poorly formatted databases of recipes currently available on the web. There are also a few well designed recipe database ebooks available.
But I am not sure if there is an ebook that let's you contact others who have made the recipe you are thinking about cooking and asking them via video chat what they thought of the recipe. A twitter style feed for each recipe could take the place of video chat of course and would be easier to implement. But still, that is just taking a website and packaging it into an epub, but epubs are just webpages after all, rendered in an interesting way.
For those with buckets of money I suppose you could order a half hour of a professional chefs time through the ebook. You could prop your ereader/tablet on the counter and then have the chef yell at you while you mangle their recipe.
A community written cooking ebook would be nice too, where a recipe in the book is able to be altered through some user voting mechanism.
What would you like from your cooking ebooks?