We are in the early stages of using the Automation Cloud tool. There are a number of groups that would like to access other workflows to get ideas or to see how the workflow actually works (through Workflow Testing function), but they cannot unless they are listed as a Workflow Owner. The problem here is any Workflow owner (especially new users) can make a change to the workflow without understanding it will affect the workflow that someone else is building. When someone is listed as a Business owner, they can see the workflows in their list of workflows, but they cannot access the actual workflow and test it. Business owners should be able to view the workflow and run a test if desired without the Workflow owner being involved. I, as a Workflow owner, understand I must give access to a specific user or all users (Everyone) so they should be able to view the workflow. Please consider adding this functionality.
I agree that the workflows should be accessible to designers and above if listed as a business owner. Right now they can see it in their workflow listings but can't open it to sneak a peak and see how another designer built something.
However, I do not agree with letting them "test it". They could still break stuff if trying to run "tests" when connectors are incorporated into the build. Maybe that would be ok if it restricts workflow testing for business owners if in production mode. Workflow testing still triggers live emails to fire off and SharePoint actions still work and will update items, create items, update permissions etc to a list item or library document even in development mode.
Def make this an optional feature in tenant settings if this idea ever transpires, some customers may not want this.
I would suggest creating another NAC tenant to use as a sandbox with restricted connections etc. Just export ones from your production one and import them into your sandbox one. From there, just add everyone as an owner after you configure it the way you want. You can always use version history if you ever need to go back to how it was originally because someone updated it or did something wacky. And it they delete it you always have the production one to export and import back into your sandbox.