Why I am leading prayers?

I am, so to speak, back in business as prayer leader.  It's gotten to where I make my way to the bima (prayer stand) as a matter of course unless the Gabbai informs me that someone has a Yahrzeit.  I've continued to ask myself why.  Why does a mourner have preference to lead prayers?

Since the Shiva concluded, I've been making my way, slowly, through Leon Wieseltier's book "Kaddish."  It's not really a book in the normal sense.  Rather, it contains translations of Jewish sources related to kaddish and the child-parent relationship, interspersed with his reflections of saying kaddish.  On page 366 (the book is 585 pages, so at the rate I'm going, I should finish before my mother's first Yahrzeit), he brings sources that address my question.  It turns out that, not surprisingly, there is a machloket (difference of opinion) about the status of mourner as prayer leader.  According to the Shulchan Aruch, the classic 16th century code of Jewish law, the mourner should lead prayers only as a last resort.  However, according to the Rama, Rabbi Moses Isserles, whose gloss on the Shulchan Aruch records the Ashkanazi practice, the mourner should lead prayers.  A later authority (Solomon Luria) explains why: "because the King of Kings prefers broken vessels."  As Wieseltier beautifully puts it, "The opinion of the former is that sorrow depletes a man.  The opinion of the latter is that sorrow deepens the man."  (page 367)

It is comforting to know that the Rabbinic tradition recognizes the contradiction between brokenness and leadership.  I am chosen to lead because my heart is broken.  I have my answer.