Now replying to Daniel, who posted while I wrote this one:

AbiWord Common: This one is easy - in 2.6 we eliminated the difference between the gnome and gtk-only builds of AbiWord.  The only difference is now a configure switch for gnomevfs, and given that I have used an AbiWord "non-gnomevfs" build on the GVFS FUSE fallback with much more success than over gnomevfs, I have disabled gnomevfs in all cases to provide the best user experience.  As such, there was no longer a need for the abiword/abiword-gnome and abiword-common schism, and so the packaging has been simplified to only have the single AbiWord package, plus docs, plugins that bring in extra dependencies, and plugins that bring in GNOME dependencies.

AbiWord Plugins - yes, it lost a lot of content because I have moved most plugins (those that don't bring in large or unreasonable depenedencies) into the main AbiWord package.  This includes ODT import/export, OOXML import, and more.  The plugin/core distinction, in most cases, is development-only, and should not be construed to require separate packaging downstream.  In this case, we were getting a _lot_ of bugs complaining about the lack of ODT support in Ubuntu's AbiWord while it was in fact just that the abiword-plugins package is not an obvious thing to install to get what is becoming essential file format support.  This fixes a host of Launchpad bugs and dupes.

plugins-gnome - Hmm, it should have a goffice plugin in it now, but here's the deal there.  Since AbiWord uses libgnomeprint since we don't have a Cairo backend yet, we need a 0.4 release of libgoffice.  In ppa18 I fixed this so it should have built and picked this up.  I see I somehow missed a change to the abiword-plugins-gnome.files list, and so ppa19 will have this plugin moved there.  However, I anticipate this package going empty or perhaps becoming its own source package in Universe for 2.6, because at this time, the only gnome plugins are:
GDA - unmaintained, requires an ancient version of libgda, not recommended for use
gnomescan - requires libgnomescan which is in Universe, and furthermore my initial build tests with it were not successful.
goffice - requires an older version of goffice which is in Universe but does in fact work.  To remove this plugin, just remove the libgoffice-0-dev build-dep and the plugin will disable automatically.
I did not want to remove it yet to avoid chaos in case we did get a GNOME plugin working and to minimize the number of "optional" changes.

Dev files: Yes, that's for the abiwidget embedding of AbiWord, used by Sugar's (OLPC/XO) Write application.  After checking again with the maintainers upstream, we don't want a abiword-dev package for 2.6, though we will for 2.7/8.  As I believe there is work to have a sugar emulator in Ubuntu, I did not remove these files in the packaging process.

RE: Debian - from what I saw earlier in this bug the Debian maintainer is MIA.  However, I'd be more than happy to work with that individual to move this packaging work "upstream" so to speak to Debian.  Most of the changes were in fact necessary, considering the improvements to the build system and the application in general that 2.6 brought.  (2.8 will bring even more - an entirely new, sane autoconf build system and a essentially unified source tree, so in that case we'll want to plan ahead and get a 2.7 in during the alpha cycle.)  I did my best to work within the framework of the existing packaging, while ensuring Ubuntu didn't miss out on the improvements brought by upstream during this cycle.  I'd suggest that the new package is in fact simpler (make install now does "the right thing" so we use it instead of doing a lot of manual file copying prone to introducing picky packaging errors) and easier to maintain, and I would have done more simplification except that I know that such changes would probably not be accepted.  I do plan to "stick around" and maintain this package, updating/applying patches and ensuring that an updated AbiWord is in future Ubuntu releases as well.  During the Intrepid cycle, I'd like to clean up the package more, and during intrepid or intrepid+1 introduce 2.7/8 depending on upstream release timings.  I won't be going away :)

Thanks for the feedback - I am pushing ppa19 right now with the goffice fix.  Please let me know if any other changes are required before sponsorship and upload.