This should be an interesting series to follow. Matthew Paul Thomas will be posting updates in the coming months to his identification of 15 usability problems with free (open source) software "Why Free Software has poor usability, and how to improve it" (211 Kb .pdf pulled from archive.org) that he posted on August 1. He plans to present an example for how to solve each one of the problems he's identified.
The Web Diva for the Accessible Techcomm website since 2012. Fellow of the Society for Technical Communication. STC member since June 1979. A founder and former webmaster for the STC Special Needs Committee, which became the STC AccessAbility SIG (2001-2011).