It'd be nice to have an option to cancel a running migration. Since the default is 100Mbps, I've accidentally start the migration at a low speed multiple times. Being able to cancel and restart it would be great.
Second suggestion:
Is it possible to remove the 100Mbps default speed (or allow the default to be changed) during a migration. I use dedicated nics between the servers, so throttling it to 100mbit by default is counterproductive.