Our backend is Perl. The managing IT departments above us want us to convert but can't demonstrate any reasons for doing so. If we did move the entire backend to a different language or architecture, our 'success' mode would be that absolutely nothing changed.

Their standard answer is that consolidation on single approach makes management easier. Our response is that architecture needs to be chosen for results, not ease of management. The reason those other IT departments have management issues in the first place is that they attempt to use all-in-one solutions in place of thoughtful, elegant design.

Our entire system runs on 2 $8000 servers. Those servers are just barely powerful enough to run the management software they use!