It would be very useful to be able to tick on a "recursive" option so you can rename not only the files in the current directory but all files in subsequent directories as well so you don't have to do them one-by-one. The same would be nice for the directory rename tab as well so it would recursively rename the subdirectories just like it would the files.
We had this option before but when ported to GTK-Perl3 the code needed to be rewritten and never had a chance to do it again. I don't like GTK-Perl and are not maintaining this project no longer.
We need someone to code it. Or you can use an old version of GPRename 1.x which had the option. Not sure if it can still run however.