Originally Posted by JSWolf
I see the same thing for other companies as well. Not just Sony. But we'll just have to wait and see if publishers force their hand when the new ePub spec is released.
The biggest block of changes in the upcoming ePub3 spec is the HTML5 elements - Video tag, Canvas tag, et al and JS support. On an eInk screen, and especially eInk devices with no network connectivity(ie 350/650 vs 950) - support for this would seem to be a less than compelling use case.
However vertical text support (among other things needed to do good layout of CCJK text) is also in the ePub3 spec, and Japanese text layout in ePub may be a compelling use case for Sony.