I decided against doing that for the simple workflow as being prompted every time you hit the deploy button would soon get annoying whilst you've actively developing/testing a flow. That was the overwhelming feedback we got when I originally floated the idea of the simple workflow.
I've no doubt there will be a way to balance the two - but as yet, it hasn't presented itself.
One option, that git allows, is to amend the last commit's message. As long as you haven't pushed the commit to a remote yet, then we could build in something to support that; so you can continue clicking Deploy as much as you want, with a new commit being created each time, but when you do something note-worthy, you can amend its commit after clicking deploy.