St. Gloriana would allow Miho to take care of some unfinished business, having lost to St. Gloriana twice thus far, and also the only team to ever beat her AFAIK. On the other hand, Kuromorimine would allow a Miho vs Erika showdown. I'm leaning more towards a St. Gloriana finals though, since we've already seen what an Ooarai vs Kuromorimine finale is like.

For a totally defies expectations finale, expect to see a Keizoku vs St. Gloriana or Kuromorimine. That would take a whole lot of boldness to pull off though.