Thank you for the thoughtful feedback! In general this thread has been very effective at getting to the most difficult decisions we had to make when developing this proposal, which is a very good sign.
The most common piece of feedback remaining in this thread is that shortestEditScript(from:) is an unwieldy name for a method. This is true, and wasn't the case with the API that was pitched. After chatting with @Douglas_Gregor and other members of the team, I've pushed a PR that renames the method back to difference(from:).