A user emailed asking if there was a way to use all this launching infrastructure to get ExifTool's raw no-args output which is a full list of metadata found in an image.
Adding a List getAllMeta() method is a possibility, but a sloppy solution to a shortcoming that the user should be able to extend and solve themself if the base implementation was more flexible.
This also points to the problem of having enum-defined Tags. It makes usage super nice and intuitive, but extension impossible.
Need to think about this more.