Without having too much network and administration knowledge, note that having Perl installed locally has the added advantage of reducing the network traffic. Many Perl modules are relatively small files, so loading them adds some network latency if you load them from a remote location.

Of course, by carefully setting up PERL5LIB, you can make it so that each Perl tries the local directory first before falling back onto the network share, which would get you easier upgrading at the price of confusion when you install a newer version on the network and the older, local version is used instead.