#4. Murphy would be a great tag team partner for Dominik
It's no secret that Murphy has the definition of an explosive offence and that characteristic would mesh quite nicely if he teamed with Dominik in some capacity. It might even be an interesting way to insert the two in the tag team division and eventually have them win the championships.
Maybe Seth Rollins finds himself a new disciple after the departure of Murphy and uses them to do battle with the newly formed group. If WWE wanted to go further than that, they could incorporate the tag team titles into the picture and make it more than a vengeance story.
In the end, using Murphy as a tag team partner for Dominik would be a great way to settle him in as a Superstar. It would give him valuable experience in the process and also continue the storyline with Rollins. It could even result in a sort of passing of the torch moment, which would really benefit Dominik's career.