But this runs in direct opposition to the title-matching rejection algorithm that is in place. (If posters preserve an article title properly, their attempts to repost are intercepted and redirected to the predecessor.)
If it is intended that duplicates be allowed, then perhaps the discussion threads for such duplicates should be merged together, rather than getting such posters in the habit of not honoring original titles.
There's no title-matching algorithm. The duplicate detector only considers URLs.
Beyond that, I'm not sure I get your point. It's definitely intended that reposts be allowed if (and only if) a story hasn't had attention in about a year. You have to change the URL slightly to make the repost work, and that's by design. Merging threads doesn't solve the problem we're talking about here, where the previous post didn't get much attention, since you'd be merging into a dead thread. The problem merging solves is the opposite one, when you have multiple active threads on the same story, and we do merge threads when we see that.
Better dupe detection is on our list to work on, but it's a harder problem than it sounds and I don't know when we'll get to it.
If it is intended that duplicates be allowed, then perhaps the discussion threads for such duplicates should be merged together, rather than getting such posters in the habit of not honoring original titles.