Sean,
Almost all of the activity of wg-ros-pkg these days is getting ready for the electric release, and the refactoring we're doing for arm_navigation is a big part of that. We're also increasingly moving away from shoving everything into wg-ros-pkg to making projects on kforge.ros.org that may have one or more associated repositories. For electric we're collapsing the core stacks associated with arm_navigation into two stacks - arm_navigation and arm_navigation_experimental. These stacks are now in separate mercurial repos in the Arm Navigation project: https://kforge.ros.org/project/armnavigation/ . The arm navigation stack has the new arm_navigation_msgs package - you can check out the very latest and greatest of these stacks by overlaying the following using rosinstall:
The refactoring we've been doing has not yet been released into the unstable debs but that should be happening very soon - for now if you want to check it out you'll have to pull from source. But I will warn you that things are very unstable - things should settle down soon as we've got an impending feature freeze.