Lock a Task so that it can serve as a template for future tasks
You should be able to lock a task so that it can only be edited by certain people, and then that task can be copied and used as a template for future tasks (with the same description, check-list items, etc.). If you had multiple template tasks (for tasks that repeat), then users could choose which template they want.
This would avoid users accidentally changing/deleting template tasks that are already in Planner.
Erik Kristiansen commented
I think a better solution could to when you click the add task button to select a template. The templates could be stored in the "plan" you are working in, and/or in your account.
The templates stored in the plan are available to all the users of said plan, While the templates stored for the user is accessible in all plans by that user