I would like to see a standalone reader for Windows. Now, yes, I know we have Logos for that. Let me explain.
Sometimes I just want to read a book, I don't want all of my study tools, this is especially true with textbooks for school. Logos taxes the system a lot for just reading.
Also, this would allow users with cheap Windows tablets that may not be able to run Logos full blown, and may not always have a connection to the web, to still enjoy reading their library.