I had gone through a similar evaluation of content vs aspect ratio when migrating from 4:3 TV screens to HDTV screens. In the end, the landscape nature of viewing TV/Movies allows one to enjoy the content better on a 16:9 display.
However, most books are read in a portrait orientation, and as a result, that's the way my ebook device should display page content, IMHO. But is the 4:3 aspect ratio the optimal screen size? Historically it is, but what should the BEST aspect ratio be?
I voted for Other!
Perhaps a bit of math may shed the light on our ultimate reading enjoyment, namely that
Golden Ratio. Using a
Golden Ratio calculator, to retain the same width more or less, I would like to see current 5" and 6" e-ink use a screen size of 633 x 1024 while larger e-ink devices could use say 742 x 1200 (or 791 x 1280). These all retain the Golden Ratio!!!
I've summarized various sources/uses of page content as well as which current ebook readers best suit them in the following table: