[OtterBooks]

Room for advancement is somewhat limited with a dedicated purpose device, but there's still progress to be had. Display quality and cpu speed are where the advancements will likely be focused, along with software tweaking.

We can speculate about uber-devices that provide displays that can both simulate paper and provide full motion multimedia etc and so forth. Short-term, though, I think we're gonna see contrast/resolution improvements, speed improvements, and then a brief plateau until a major display tech evolution occurs. Color e-ink will be somewhere in there, after a generation or two of monochrome improvements. imo.

Touch/button navigation is a design and ergonomics issue, not so much a result of technology advancements. The decisions there are gonna rest on consumer preference, which itself is in a stage of development.