Occasionally, a subscriber on my list will change their email address (because of change of ISP or similar). When this happens, any campaign sent to them shows as undeliverable. Once a campaign is sent to a subscriber, that same campaign will not be sent again.
I would like to suggest that if the list owner modifies the email address of a subscriber, and subsequently requeues a campaign that had been sent to the OLD email address, the system should allow the message to be delivered to the same subscriber, at the new email address.
If this is not possible, I’d like to suggest that a subscriber account be clonable, so when the new account is created (with a new email address), the history of the old account is transferred over.