I'm thinking it would be useful if the rules in smartlists allowed for more than simple binary inclusion or exclusion. For example, it would be slick if I could have a "Rock" Smartlist that contained songs whos Genre was prefixed with "Rock". e.g. Rock: Oldies, Rock: Classics, Rock: 70's, etc. In addition to 'Prefixed' it would be nice to have 'Contains' so that "General Rock" or "Southern Rock" would also be picked up (some might argue these should be "Rock: General" and "Rock: Southern" but why go down that path again?).
Taking this a step further it would be slick if relational operators were allowed for numeric tags (e.g. Year, Rating) so that one could do "Rock: 80's" smartlist with (Year>79 AND Year<90) type rules.
By the way, can anyone tell me why the "Advanced<<" button is grayed out when I'm working on smartlist rules?