Don't you think that would be unfair to anyone who posted in your threads?
If you need the power just to delete double post threads, just rename the duplicate thread to something like "dp" and if they're feeling generous, one of the mods will come along and delete it for ya.
I don't think YOU understand. Members are not given the power to delete their threads because it's not fair to the people who post to those threads. It's prevention of confusion and frustration. End of discussion.