Essentially an expansion of current system that rather that just being "all/any of the following" it can be "all/any of these" AND/OR "all/any of these"
So I could say:
All these: Condition A, Condition B, Condition C
All these: Condition D, Condition E, Condition F
So it would play all cases where A,B,C are ALL true for a track and likewise all tracks where D,E,F are ALL true, provided they have Condition X true.
This can roughly be achieved currently (and awkwardly) by making 3 separate autoplaylists (one for A,B,C and one for D,E,F and one tying them together, for example). However, current setup means it takes some time to set up and it is not very practical, especially if you want to try a bunch of different arrangements without getting absurd with the number of playlists you're using.