MongoDB Perl Wrapper
I'm the lead engineer for the MongoDB Perl driver with a couple of thoughts for you:


you're using 'authenticate', which is for a very old version of the driver which is not recommended for use.  In the v1.x series, you should provide username/password in the URI or in MongoClient parameters.
Most of the value of this module seems to be setting parameters and calling connect.  I would suggest doing that with a function, not a module and then just using the resulting MongoDB::MongoClient object directly.