Let's be honest here. As readers, we never asked for interactivity in our books, and the interactivity we need we won't get, because both e-reader vendors and publishers view us as cattle to be herded, locked up, and milked until we die.
Publishers' attitudes towards readers are roughly analogous to that of a tax collector to a tax payer. It has escaped them that they aren't as inevitable as death or taxes—that they operate in a free market, competing with other forms of entertainment and other, more easy-going, publishers.
E-reader vendors, on the other hand, operate under the assumption that competition is constant, never-ending, brutal, and ruthless, and will apply whatever method they can think of to grab and maintain advantage.
They may not state it plainly but it's clear from their behavior that features that could even remotely diminish platform lock-in aren't likely to be implemented.
Which is a pity, because most of the features that readers need are features that might be seen to compromise lock-in. They would all increase platform loyalty but decrease lock-in.
For example, the single most valuable—productivity boosting—feature that an e-reader platform could add would be a complete and open API for bookmarks, highlights, and notes.
If I could have all of my highlights and notes automatically sync—marked up and tagged—to my Simplenote account, that would trump any design feature or widget e-reader vendors can possibly think of.
Reading is a big part of the writing process, always has been. It's been the one part of writing that computers haven't helped improve so far. E-reader platforms have the chance to make history by integrating their reading tools with existing writing tools
Imagine every Kindle highlight or note automatically appearing in Evernote.
Imagine all of your Kobo notes and highlights syncing to Simplenote and from there, as if by magic, into Notational Velocity, Scrivener, or Tinderbox.
Imagine all of your iBooks data, your scribbles, bookmarks, highlights, available through a simple API call to all of your iOS writing apps. (Only with permission, of course.)
While all of these amazing applications have revolutionized the art and craft of writing, their reach is limited to what we can put into them. The one transformative feature that e-reader platforms can add that isn't reliant on developers, publishers, or file formats, is open access to reader's annotations (highlights and notes).