I think this would save members and moderators a lot of time. When you submit a post a script tries to detect if a post made in the last few days looks like a duplicate and presents you with a list of recent posts that look similar. A lot less merging, splicing, frustration, etc. I think, especially with posts based on news stories.
(actually I wasted some time before posting this very post trying to determine if there was another duplicate post warning discussion - for all I know there is and I just didn't find it despite using the site search function).