As a development manager I need to be able to breakdown tasks that are larger than one sprint, ie Epics, into subtasks that can be delivered in individual sprints. So I would need the ability to add subtasks to sprints without having the whole task added. This will also help with sprint progress management since subtasks currently can not change status without the full task moving. So if I have multiple devs working on sub-tasks within a task they can't track independently on a board.