This is a great idea, we’re always looking to improve the experience of creating an action. 

In your scenario would the default assignee be a specific role at a specific location, eg actions are always assigned to the ‘maintenance manager’ at that site or location? 

Would you know any other information about an action as you’re creating the template? Eg the priority, description or label? 

ps You can now configure default due dates based on the priority of the action. More info on how to configure that can be found here

I can’t speak for the OP, but in my organization, it would be very helpful to be able to set a default assignee, priority, description, and label.

Sounds very useful for the population of repeat actions in a defined format.