It would be very cool if I can move tickets over to another repository.
See for example you have a main branch of your project and someone creates a new fork to add some cool new features. Now a user reports a bug regarding that new repository while that bug exists in the main branch too. This is obviously wrong and should be moved to the main repository since the aim of that fork is just not fixing annoying bugs.
There are plenty other examples I miss right now but that feature would be very cool!