The thing that gets to me somewhat with technology is people tend to pay more for more features that they might not always use. Now hardware isn't something that can be a la cart but just consider how far we've come.
10 years ago pda's went from b&w to color...the only problem at the time was the color was well...poor. reduced battery life so the gain wasn't much. Yes one can make the argument towards a color e book reader but honestly outside of a book cover and a graphic novel I don't see THAT much of a gain.
I think it could be possible that amazon could release a touch screen with a next kindle but they are probably keeping a keen on on how the screens on the ipad turn out. Touch screens are no problem to make but the applications of them aren't always the best...palm did quite a bit on this but you used a stylus...not fingers (for the most part)....
there's nothing wrong with the ipad but with any invention just think of what the primary purpose is...when items attempt to achieve a secondary or third purpose it does not always work as well as what is intended..i.e. toaster ovens and instant coffee