The 'resend' feature in the new Group Email insights dashboard is for use when updating a bounced email address. Our thinking in adding this feature was to facilitate 're-sending' and email to an address that had bounced.
We have an open enhancement request to alter/update this feature to 'resend' and email campaign based on some filter or action. For example, re-send based on everyone who opened and email, or did not open an email.
This request is part of a larger request called "Marketing Automations" - where campaigns can have scheduled actions including future dated send-outs, at a predefined time or time lapse, and with filtered recipients. For example, to promote a program initially, then resend to addresses who did not open it, and then send a different email as a reminder or "last call" notice.
We do not have a final specification or release date for this enhancement. We will fine-tune this specification and examine scheduling/priority input from the Foundation Advisory Board.