After some thinking I would say, that this would be a short-term solution, which would help of course, and I'd happy to have it rather than to stick with the current system. But I do not think that it works reliable enough and doubt it makes us happy in the long run
For me the following logic would be perfect: Sort everything except the lowest level. I suppose PP knows if the browse list currently showing has subfolders or not. If not, then this is either an album, compilation, or a playlist, where sorting is not desired normally. This could still be combined with a number limit, i.e. if more than n tracks on the lowet level, then sort.
If you want to avoid a button, then you could add two config settings:
* Sort browse list if more than n tracks: 30 (default)
* Sort on lowest level if more than n tracks: 30 (so, by default PP behaves like now)
I think with these settings a button to toggle sort would be the cream on top, but I could live without it.