There could be optional support for using Google's closure compiler for minifying the JS output using rest-gen. It wouldn't be very hard to do considering it itself is a rest api.
I will work on this Tuesday (June 9th, 2015) if people think this is a good idea. Additionally, if people have other well known minifiers they would like to use let me know. I could also add arbitrary support by adding a flag which can use a local executable.