There is a problem with duplicates not being handled well on the site over time as outlined here. Sometimes the chain leading to the best canonical question is too long, sometimes it doesn't even link to the best canonical, sometimes it links to a deleted question, and sometimes a post closed before they changed the process will link to an unanswered question.
I would like to request that Trusted Users (20k+) be allowed to change the Close as Duplicate link so that those questions could all eventually be pointed towards a non-deleted non-closed answered canonical question (optimally).
I think it would be best if we had a queue for this, so that it would take multiple Trusted Users to actually implement the change.