I would love to see a trigger in Flow for when a Planner task changes from one bucket to another.
I would have a lot of use for this as well. We want to link Planner to Sharepoint List and updates would be done depending on the bucket location of tasks.
Please vote for my idea to create the trigger When a task is modified
The more generic trigger would allow to do mostly anything with Flow and Planner under the condition all task atributes are available in Flow.