W Page, I understand that you're asking for this / these kinds of things. But I also agree with Martin that the usability is touching everything in Moodle and therefore is already discussed in a lot of places. Mostly in the module forums, where they belong. The Themes forum might be a place to raise issues dealing with the standard theme, for example. Another place for overall changes is the general developers forum.
What you and others conserned about the usability of Moodle could do, is to have a real usability study of Moodle. If possible, with real courses and real students. Study the students, make them say out loud what they are thinking while trying to accomplish tasks in Moodle and so on. This would make the bulk of comments to touch the existing issues instead of having a bulleted list of improvement ideas after a brainstorming session. These new ideas are usually not tested against anything real, so they might require a lot of work but might give nothing.