My own thought is very close to yours, wulfn1: that at some point a person might wish to change what was written for any of a host of possible reasons. There should be a time limit, allowing for global time differences and incidental server problems which could happen.
Maybe people should be allowed to do that...after all, (and not to trivialize an important issue in some cases) we're not rewriting a very significant piece of legislation nor a life/death determining document.
That said, a time stamp on edited comments might (if folks agree) appear under (but in the same box) as the original. a reason for the edit would also have to be given and printed under that new comment:
"The original comment above was edited at XYZ o'clock by the maker for the for the following reason: " which would have to be filled in to have the edited comment added say after a 5-10 minute edit margain. People should, however weigh their words and be held to that responsibility.
Thus the original would continue to appear, only with comment in red below it and then, below that the edited comment.
I think that might satisfy folks....
*this is not included in the listed suggestions. Only when this can be amicably worked out (or an approximation of a final opinion) will this be added...i claim author bias as the reason.