I think leaving CPAN out of the RPM is a *very good idea*.
I cannot begin to tell you how many problems CPAN has caused when mixed with RPM packages coming from the distro and/or from alternate repositories.
CPAN wants to upgrade packages it has no business touching. It wants to install things into locations that disagree with RPM. It leads to multiple copies of the same thing installed into slightly different places making it impossible to tell exactly what copy of SSL is crashing your app.