When a moderator edits a question, it shouldn't be reversible by a regular user. For instance, a mod sees a flag about a 1-rep user ranting in their post, and edits the post to get rid of it. If that 1-rep user returns and re-edits to insert the rant again, that mod won't know unless someone else re-flags.
I would suggest that it require a substantial amount of rep to change a post once a moderator has edited it. Possibly even restrict this ability to 10k users.
Edit: Perhaps, rather than blocking completely, any edits thereafter by low rep users (the level of rep being in question), those edits just go into the edit queue for review and approval by users with the required rep.