Novice users are reporting difficulty in finding the preferences for the window list applet, even among people in the habit of right-clicking, since right-clicking in the applet typically exposes window management functionality.  Yes, one can right-click on the resize grip, but it's (1) non-obvious, and (2) tiny.  This was discussed in passing in http://bugzilla.gnome.org/show_bug.cgi?id=72628 several years back, FWIW.

A fresh look from the usability team might yield some improvement.  I'm afraid I have no specific suggestions (other than the merged menu, which Havoc mentions but dismisses as confusing, and the possibility of putting the setting "somewhere else", though putting it in a control center applet really doesn't make it that much more discoverable).