It would be a nice feature to have the possibility to define URL aliases for a repository (on the repository admin page).
For example if the name/URL changes for some reason this change will break any future pushes (due to changed URL).
The possibility of defining URL aliases would solve this issue, a new URL alias would be defined by the repository administrator when such an alias is needed.
This feature could be also integrated into the repository admin page e.g. when the repository name is changed Bitbucket would automatically ask the user if he/she wants to define an alias for the former repository name as a redirect, something similar to what is happening now when you delete a repository