A Kindle killer has to have eInk.
People who use the Kindle and other ebook readers don't use it because they want a high tech gadget with lots of options, they use one because the eink technology allows for easy reading. You could buy and read ebooks on the iPad but the glossy and backlit display will be far worse on your eyes.
People who want color, video and so on don't buy a Kindle, people who are avid readers do.
******** this whole "LCD is bad for your eyes" crap is not founded on any comparable study. Again.. there are millions working on LCD screens all day, and I don't see glasses maker stock prices going up lately..
Granted e-ink is easy to read, but nowhere near a killer feature of an e-book reader. The killer feature is the battery life..