Yes, creating a dialog-based config menu would not be difficult at all. I simply haven't got around to doing so yet; the idea only came up just a short time before V1.37n's release.
I'll look into how practical it is to add right-click to the remappable keys (and if I were to do that, middle-click (currently hardcoded to Pause) should probably be added too; maybe even left-click too?). One thing that comes to mind is the slightly different behaviour in terms of highlighting between the old and new options - currently (or at least prior to hotkeys becoming remappable beyond this single swap option), if Right Click was configured to be highlight, it was just a matter of point, right-click. However, if Ctrl was, it was point, hold ctrl, left-click.
Perhaps then, the replacement for this option is to determine whether highlighting is just a matter of point, click; or whether it's a matter of point, hold modifier, click. However, this would then raise the question - should force walker selection *also* have this toggle? The counterargument here being that unlike highlight, which in most games that support it (L3D comes to mind as an exception) it's always been a matter of directly clicking, and thus there should at least be an option to (if it's assigned to a mouse button) work from a direct click; while priority invert has never been that way, it's always (even when on a mouse button) been "hold priority invert, normal click lemming".