I have found a bit more about possible directions for Acrobat. Kurt Foss has a blog as part of Acrobat Users and this links to a preview of what to expect from MAX, the Adobe meeting for developers and designers.
However it seems to be mostly about Flash. How to embed Flash content in a PDF. How to create a portfolio, a Flash intro and menu that contains several PDF files. How to use various types of code to create Flash menus. There is nothing I can see about PDF and XML or how to move text between various file formats.
Maybe I have just lost touch with where the concern is. I do realise there is a current debate about Apple TV compared to Google TV and other Apple / Flash choices. Only the paranoid survive and this challenge has to be met. But the same kind of message may not suit everyone. There are still people using Acrobat who are interested in documents that are mostly text with some flat graphics.
As far as I known there is no current development on MARS, the XML rewrite of the PDF format. Maybe this is not of great concern if workarounds exist for the problems identified previously. The tool for checking a PDFXML file can also be used for EPUB. There is very little info on how Adobe supports EPUB.
A PDF portfolio could be a better option than a zip file inside an organisation that stripped away zip attachments as a security risk. Also a PDF file containing Flash could get into some organisations where Flash is usually banned. These are interesting points but not advancing PDF as such.
I did try out portfolios when Acrobat 9 was released. I found that the people I sent them to were reluctant to have to upgrade just to read them. So I sent the PDF either file by file or with a PDF menu. Recently I notice Gmail has a reader for PDF attachments that launches quite quickly. It may be some form of Flash paper, I don't know. Scribd is working on HTML5 but the current version is based on Flash. Thing is, they seem to actually like documents. On an Adobe site I usually feel I should be losing interest in text, animation is the only way to go.
There will be a session at MAX on "Dynamic PDF", I guess this is another word for Flash.
There seems to be no news about Acrobat.com or Buzzword. Acrobat 10 will be announced presumably to encourage upgrades. But is the dektop the only option? What versions of the software capability will be available online?
My guess is that as PDF and EPUB are now open standards, Adobe will not have the same energy for explaining how they relate to these formats. The challenge of Apple TV to the Open Screen is just too pressing. Acrobat will become another way to show off Flash. just like any other Adobe product.
Thing is though, as Acrobat moves on from PDF there may be some Acrobat users who start to look around.