Not having a keyboard would make it a pain in the ass to search for content. Amazon is highly vested in making it easy for you to get more content. Yadda yadda, the keyboard aint going anywhere.
they could always go with a virtual keyboard now that the refresh times of the screen are getting better.
and you would push keys on that with what? it's not a touch screen.
Don't be that sure, I can envision a version with a single button activating the voice recognition software that will allow you to download whatever you want.
A software keyboard is much more likely. It shouldn't be too long before E Ink displays can reliably/cheaply handle touch input.