I find the current functionality of updating your test while executing it a bit clunky. Now I do understand that it is meant for small changes where big test overhauls should only be done in the test Steps tab but still I think there are some improvements to be made.

1) If a step has been edited during a run, PT should ask the user if he wishes to 'Update Original test' before navigating away from the page. I find that I often update a step but forget to click the button to update the test at the end.
2) It will be useful to be able to add attachments that are appended to the test step (and not the instance step). For example what better time to screenshot a screen and add it to a step than while executing the test?
3) It would be nice if there was a way to open all steps for editing with one click. That way you can quickly scan the tests for things to update according to the SUT or changed requirements and do it all at once.