Perhaps it is a case of: we're happy with what we have. Sure we could ask for a lot of stuff: colour screens, higher refresh rates, as well as more sophisticated typesetting and layout. Not to mention the other ideas that people are bringing up. But would that sell more ereaders? I'm not so sure, simple because books are predominantly black and white, are static pages that we read one at a time, and don't depend upon typesetting or layout to a large degree.