So I think Serato is missing the option to be able to choose which column of data you want to use from your tracks as the second priority for sorting them.

I have it automatically sorting by BPM, and then by default it sorts artists in alphabetical order for every track that I have under 128bpm. I use Mixed in key and have my track keys under "Comment", and I'm sure other SDJ users have the key of their songs under the "Key" tab.

It would be nice to choose BPM as my first priority, and then Comment so I can mix in Key easier. I could also use "Date Added" as a second priority to find my most recently added songs under certain BPMs.