I find this program to be fabulously useful. Sometimes, though, it's too big onscreen, especially with, say, two Explorer windows open at the same time. It would be nice to have the option to switch to a 'simplified' GUI, like so...
The configuration file selection is in the file menu, where it would usually be found. The various option settings are in an options menu. Fields 2-4 are either excluded or hidden in the options menu. The file queue is hidden until opened by the "queue" button, but since there's no reason to drop anything into the output window, the whole bottom part of the screen can serve as a drop zone for the file queue, whether it's visible or not.
Another step - add 'menus' for fields 2-4, which are drop zones and allow viewing/editing by clicking or selecting the 'menu' via keyboard. Then they're fully available without taking up screen space.