House70: You can download your library at any time onto any device which has Kindle software - which is basically all platforms. Although I would also like to have an SD card slot, it just isn't all that necessary. 2GB stores a TON of books, and you have access to your all your other archived books via Amazon's Cloud. What you call copyright paranoia, many call convenience and safety. If my device is stolen or destroyed, I can just redownload everything seamlessly via Amazon. It's really no different from what Google does.
If this was a smartphone or tablet, and I want to store a bunch of movies, music, games, etc locally for speed/bandwidth purposes then of course SD cards rule. My tablet and phone both have 32GB microSD cards installed. But I have found that with my singular-purpose Kindle e-reader, I just don't need an SD card.