As I prefer functional style programming over procedural, I never really liked File::Find's "global vars interface"

That's kind of funny. File::Find has one of the most functional interfaces of any core module I can think of. I mean, its 'find' subroutine's first argument is a function. Granted, it does use funky globals instead of @_ to pass arguments to that function, but I think that's an orthogonal to its functional-ness.