I'm pleased to see this plugin have grown and it's much better than it was many time ago, good work! ;)
I would like to suggest a new feature, that I think would be a smart one.
Adding a new option to choose another DB for storing the stats. It would be easy to add three fields to specify the database name, user and password to connect to the new DB (in the same host, or adding another field to specify the host), or maybe simply an unique field to specify database name!! ;) Leaving the WordPress DB alone and more responsive without storing a lot of stats stuff ;)