As a Builder, I would like to have an emails sandbox or testing environment so that I can set up all of my rules and test who the emails go to and how they look without sending emails to real users.
Currently I have to adjust or remove all the rules entirely to test.
Forgive me if I've misunderstood what you are asking for, but on the interface side, I have a check-box that allows the user to decide whether an email is sent or not. You then add that as a condition on your email rules in the builder side.
You could have one yes/no field...checkbox for your test emails and a second for your production email rules... This would atleast allow you to decide which email type should be sent and if it should be sent.
As far as a feature request, you have my vote.