Hi,
I finally tested what you described and now it makes sense however the problem with the server repositories is that you can not upload files via Moodle. So a teacher has to have some sort of ftp acces, and have the server file open in another window, it doesn't seem much to do but still...
I hope a search engine will be available soon in the file picker! those server file location wouldn't bother me so much. I counted today, in order to add a file one has to click 8 times!