The " Parameterization:" section isn't clearly a problem
Parameterization is a cause of possible interoperability and security problems. In the specific case of IDNA, endorsing having different user agents doing differ things doesn't further the goal of interop.
If choices are implementation dependent, that should be justified.
Also from Bjoern http://www.ietf.org/mail-archive/web/apps-discuss/current/msg13507.html
The " Parameterization:" section isn't clearly a problem
Parameterization is a cause of possible interoperability and security problems. In the specific case of IDNA, endorsing having different user agents doing differ things doesn't further the goal of interop.
If choices are implementation dependent, that should be justified.