As one of innumerable admins who work long and fluctuating hours, and who still perform some migrations through the GUI, it would be super awesome if there were a visual indicator of source and destination sites in the migration interface. Even better, a "Copy From" and "Copy To" heading over each column. When you're preparing to merge a large site collection into a blank target site at 2 in the morning, it would be very reassuring to know beyond a shadow of doubt that I'm not erasing one of the company's primary knowledge portals. The URLs can be very similar between source and destination, and the names are usually the same, or become the same duirng the migration. It would make a big difference to an ape like me.