This is perhaps treading close to the enhancement requests that are already in 
bugzilla, for example 380 - Automatic Playlists.

As a stats enhancement, it would be nice to have a stats type selection to 
select either "Top Artists", "Top Albums", "Top Songs" and possibly others 
(maybe top radio stations).

It would be nice to have an inverse stats selection "Least accessed", which 
could be used it to find albums that haven't been played in a while (or maybe 
a selection mode "Old Music" which is the opposite of "New Music").

Then Random Mix could be weighted (via a pref or by providing other random mix 
selection options) to bias towards popular music or non-popular music.