Obviously, a command-line program would be the first step towards usability. (And way easier than a GUI program, obviously.) Let this stand as my to-do for that command-line utility.
Also: I think it's time to admit that I'm going to write the UI portions of the Xlat project in Decl, not plain Perl. This will probably require the definition of a Xlat::Declarative module. (That's a good thing.)