It's clear to me that there is more than one model of communiction active here, more than one metaphor for our discussion. Some of what we post (Turf, the Media rooms, ToE) is indeed conversational, light or serious, middle of a crowded room or off in an intimate corner. Some (RP and other quasifiction comes to mind) are creative endeavors. Some (Symposium threads, B-room discussions) can occasionally resemble a debate. And some (Jury Room deliberations) are unique...
Trying to find one rule to wring them all seems to me pointless and yet futile. I do not think consensus on such would ever be possible, and even IRV would leave a majority unhappy with any compromise.
So either we have forum-specific expectations on editing, and implied ownership, or we have a rule so vague that it comes down what it will anyway: common sense, courtesy, and the occasional knife fight. I mean discussion.
Should I edit that last bit? ...