It looks like your plugin MailChimp Integration can only be setup for a single newsletter managed by the superadmin on a network level. It's a tool 100% aimed for the network admin.
In my network, I would rather like to offer this tool to my premium members ("pro sites") as well. I want them to be able to manage their own list of members with their own MailChimp account. I think that offering such a marketing/newsletter tool to our members really could improve sales.
Would you like considering improving your plugin in this direction?