Calibre uses icons, but it is not entirely icon-driven. Common actions are available on a toolbar with drop-down menus. The menus don't seem very deep, yet have moderate complexity. Overall, Calibre is geared for general users: anyone who wants to manage ebooks on their reader. The program is not too complex, yet not trivial. Calibre is Free / open source software, distributed under the GNU General Public License (version 3).
I'm not saying Calibre is the program I'll go with for a case study, but I'll certainly put it on my list of possibilities.