Hey the call the format differently, they call it kepub
But I really think that page number system is not useless. As long as you have a book where you turn page, because yes you turn pages in a kobo, sony reader or any other eBook device, the page number system is not dead. When you'll start to scroll instead of turning page (which I don't like) then I'll agree page number becomes useless.
So as long as page number is concerned, and as long at is is not useless, then I think they should display it the good way, I mean having the page according the size font, so as ONE page is what fits on the screen ^^
But this is perhaps because this is an old ADE version as you said, and that new ADE version display pages the good way? Or not?
It is Adobe which have invented the eBook? I wonder why we always talk about an ADE engine, as it is just a way of display plain text, and not all eBooks come from ADE.
According to what I read on the net, Kobo uses a proprietary engine to display eBooks, an engine which can display ePub as well as kepub and some other formats.