I found an article by the scholar Barbara Reid helpful. It's titled "Matthew's Nonviolent Jesus and Violent Parables," and in it she lays out several different options for interpreting the violent treatment of many of the characters in Jesus' parables--usually at the hands of or command of the character interpreted as God or as Jesus. The article available for free on-line is a version of a more scholarly and somewhat less accessible article she published in the Catholic Biblical Quarterly. The violence is not troubling, of course, if you believe in a literal final judgment that involves Jesus sending some people to hell and others to heaven, but if you have any doubts about such a theological reality--especially the way this judgment has been carried out by Christians throughout the ages in a very non--end-of-the-world sense--then the violence is bothersome.
Also, I've been turned on to the scholar Robert Farrar Capon's books on the parables. (Thanks to Andrew Kar!) In his book Parables of Judgment, Capon finds the key verse in this parable to be the foolish slave's understanding of his master: ‘Master, I knew that you were a harsh man, reaping where you did not sow, and gathering where you did not scatter seed; so I was afraid, and I went and hid your talent in the ground. Here you have what is yours.’ His interpretation of this and other parables states that the ones who find themselves kicked out of the Kingdom are those who remove themselves. Those who believe God is a great bookkeeper who keeps score and stands ready to punish those who don't measure up to impossible odds alienate themselves.
Also in this sermon I shared Frederick Buechner's interpretation of this parable. Buechner is one of my favorite authors and he tells about growing up in fear of his father who was an alcoholic in his trilogy of memoirs: Telling Secrets, Now and Then: A Memoir of Vocation, and The Sacred Journey. I found a sermon on-line of Buechner's where he relates telling some of his experiences growing up with an alcoholic father when he was the speaker at a conference. One of those present remarked, "You are a good steward of your pain." What he took away from that comment was that instead of bottling up his pain and shutting himself off from the world, he had used it to help others and had shared what he had learned from it. This understanding of stewardship of our lives seemed to go hand in hand with Capon's understanding of the third slave shutting himself off from God.
Grace and Peace,