I was thinking about this myself. One thing I am considering doing is trying to extend
SwingInputWidget to get more complicated behaviour, and more control over the layout.
An example is the SwingColorWidget which can be used in a script as follows...
// @org.scijava.util.ColorRGB color
My initial thought is I can make groups of parameters as small classes, and make a widget for them, that organizes the fields horizontally, or has a button for a more complicated pop-up (like the color one does).
I haven't actually tried this yet, just at the planning stage... so I am very open to other strategies.