I would love to have the Amazon Kindle available as a channel, for the total convenience of reading my Amazon books on my 65" television. As there are a number of Amazon products already included, would it be possible to add the Kindle app also (if not already there which I missed somehow)?
As an aside, I am fed up with the Roku channel, starting to watch programming where down the road, it becomes a paid subscription. There should be a complete separation of free and paid programming, as a selection immediately upon entering the app. Not the sneaky setup there now is?
Aside from The Roku Channel, Roku Media Player, and a few Roku information channels, Roku doesn't create the channel apps, the channel owners do. For the most part, Roku just provides the platform on which the channel apps run.
You could contact Amazon and request they develop a Kindle reader app for Roku, but I doubt they would be receptive. It would not be a normal Roku app as it would have to read the book file from your computer or other device instead of just dealing with it as it is streamed in from their server like a normal video file.
Your best bet is probably to learn how to cast or mirror from whatever device you use to read your Kindle files to your Roku.