For the 2.3.x branch graph has been very stable, not very much development going on at all.
If you are a volunteer we could use help improving documentation of this module. Contributing a tutorial would be a great help.
IP review is underway - known issue: http://svn.geotools.org/geotools/trunk/gt/modules/extension/graph/review.txt
There is an old page here:
This content should be updated and moved to the user guide or manual.
The module maintainer will take care of assigning these issues to developers:
Remember that the module maintainer is a volunteer, and if you can help test this module please jump on the developers list and help out. Patches may be attached to the above issues for review by the module maintainer.
Although not the responsibility of the geotools module maintainer additional or related issues may be found in the the geoserver or udig bug trackers.
There is no interesting development planned at this time.