Thank you for taking the time to vote on this request. Work on this has commenced. We will email you once it is completed. Feel free to reach out if you have any additional feedback.
If you are interested in participating in the preview of this feature please email back.Mark Andrie commented
+1 for this feature, it would be great for ARM to support a sort of "-WhatIf" or "--noop" syntax where you could run this template simulation and see what would change, all the way down to the properties on a specific Resource.
I would also like to see better logging of what actually changed during a template run