This summary is from the Girardian Lectionary:
Instead of seeing the king as making Jesus' audience think of God, he argues that this king would have sparked in Jesus' audience thoughts of kings much closer to their situation in history, namely, the Herods, especially the first King Herod. Drawing from historical sources such as Josephus, Aiken shows how the Herods actually behaved in ways very similar to the king in this parable. With a monarch so brutally dictatorial, does Jesus really mean for us to think of divine kingship with this parable instead of the kind of petty dictators such as the Herods who so litter human history with victims? I find Aiken's argument persuasive -- which is also reason why I have highlighted in recent weeks an overall approach to Matthew's parables of judgment that hesitates from too easily reading the central figures of power in these parables as representing God. See the remarks in this direction for Proper 20A and Proper 22A.
So who is the positive figure in this parable that makes us think of the kingdom of heaven? The person without a wedding garment at the end who seems to intentionally take on this king's brutality. Aiken points to a verse in Matthew's Gospel which I have subsequently come to argue as central, namely, Matthew 11:12: "From the days of John the Baptist until now the kingdom of heaven has suffered violence, and the violent take it by force" (see the reflections for Advent 3A). The kingdom of heaven as suffering violence is represented in this parable not through the figure of the king who dishes it out, but in the lone figure at the end who takes it upon himself. Aiken thus also rightly brings in the figure of the Suffering Servant of Isaiah 53.