The Swing file chooser is not ideal: with the Mac or GTK look and feel it doesn't allow the selection of directories. The JavaFX file chooser is apparently much nicer, and it's apparently possible to use it with Swing (see also https://github.com/veluria/NativeJFileChooser). There are some potential problems with using it, though:
Allegedly, mixing Swing and JavaFX can get rather messy.
It's not clear how much of JavaFX would have to be dragged in and packaged as a dependency.
As of 2020, JavaFX (a.k.a. OpenJFX) development seems rather stagnant, and there are complaints about bugs that never get fixed. Using it may cause more problems than it solves.
In any case, users aren't actively complaining about the current file chooser, so this should be considered low priority.
The Swing file chooser is not ideal: with the Mac or GTK look and feel it doesn't allow the selection of directories. The JavaFX file chooser is apparently much nicer, and it's apparently possible to use it with Swing (see also https://github.com/veluria/NativeJFileChooser). There are some potential problems with using it, though:
In any case, users aren't actively complaining about the current file chooser, so this should be considered low priority.