As far as you know, there possibility for moderators or registered owner of comment to edit their comments. When editing, new edit time overwrites originally created time. For me it is not suitable, as at my site I have few moderators, that may edit users comments, and after editing it is not possible to see when user wrote this comment first time (for example in security reasons).
I propose to add new config "Store editing time" in back end, and only if it is set, editing time will overwrite created time.
As far I understood, developers in future intend to add a possibility to store edit time in separate database field (like in usual articles). But seems that it will take a lot of time, so as alternative way, I propose such config option.