I'd like a Home icon on the screens -- Button ok but screen pick is easier and seems more intuitive.
On side loaded books Calibre etc. seem to pre-set the format nicely - I set my margins to 0 and no intra paragraph line. The intra line spacing seems about right by default.
It would be nice if we could set up our own categories for our books & support some type of manipulation to get the books in these categories. Even if only supported side loaded books this would be fine.