If you have some spare time, you can propose the pull requests for the spec and tck. I don't think it is hard at all, it will mainly take you a lot of time to find the right spot(s) in the spec. (It would take us the same time as we are cold on the subject and why we can't really do it now :/ ).
With the tck change, you might need to update Hibernate Validator as well. Any small step will help further.

Cc Gunnar Morling