If the nature of your campaigns - or some of them - is such that you simply cannot afford to send incorrect or incomplete information, the Approval Workflow module is for you.
Once the campaign is ready to go in the normal manner, the "commence workflow process" button gets clicked. People with "Approver" status are sent and review all aspects of the campaign, which they either approve for sending or enter their comments as to what should be changed. Once that process is done and the campaign is approved for launch, someone with "Launcher" status can send the campaign.
To make the whole process as painless as possible, the approvers and launchers can be set up with each campaign template. They can be changed if necessary, or new people added, in seconds. Even starting from scratch, it would only take 15-20 seconds to set up the approval workflow.
Naturally everything is audited and available for review by the system administrator(s).