I think we should give less priority to the "publishing date" compared to "quality" to better handle cases like this one:
Marked as original
question vote: 18 question starred: 17 answer accepted: NO best answer vote: 17
Closed as duplicate
question vote: 33 question starred: 14 answer accepted: NO (is possible to accept it ? can't really try it) best answer vote: 108
As you can see it doesn't really matter how many upvotes the answer gets. From a point of view, this makes sense, it is duplicated, but from another point of view it would have much more sense to close the previous one.
Moreover, it doesn't really looks very useful to close a question, it doesn't really resolve the problem of unifying and centralising the knowledge (due to a the inevitable delay in closing the question).
As fas as I can see it help only to avoid abuses of the system (re-asking a stellar question) but this could be probably archived in many other ways.
I would like to think positive and propose and alternative, however it's not that easy, probably have something to do with upvotes :)
...my 2 cents :)