There are a few features most people want added to the Reader, but I think most can be implemented through a software package that changes the existing format to LRF (which a lot of people have already put a ton 'o work into). Given the fact that the device uses a static display; i.e., eink, it would be tough to get a lot of uses out of it without burning through its battery life like crazy. $ony would be smart to develop/market a software package that converts from existing formats to the more streamlined/their format (at least in regards to their system).
I'm not sure what else I would like the Reader to do than what it already does, of course, when someone comes out with a *novel* hack/feature I'll probably change my mind at that time.