notify-send not working on 14.04, but volume and brightness notifications do

FWIW, I checked against my install of Ubuntu 14.04 (64 bit) and have the same dpkg... output that you have, plus a couple of others from other apps being installed.

Try notify-send "summary" "body" and also try with the --urgency=critical to see if that has any effect. The latter is effective when notify-send is being suppressed because a video is playing.

Otherwise, perhaps install a 3rd party indicator which has notifications and see if that works.

Found the following from a comment at this question:

Try purging notification-daemon: sudo apt-get purge notification-daemon then try apt-get autoremove. Make sure notify-osd is installed: sudo apt-get install --reinstall notify-osd and restart.