I agree with most everything Chris Boyle said.
UCF wanted Nikai Martinez to remain, but Gus is a penny pincher who refused to pay more than fair market value for his services. Through Nikai, Gus sent a message to the other guys about the end result of unreconcilable differences about money.
Regarding the quarterback room, I think most UCF fans are content with the group "as is" because (a) they want Gus to develop his own guys (unrealistic in the current transfer climate) and because (b) KJ Jefferson has zero injury history.
If UCF enrolls transfer edges Nyjalik Kelly and target Cam Riley (who can also play Sam linebacker and Mike linebacker) and retains all its current defensive linemen, the Knights will field the top defensive line unit in the entire Big 12.
Boyle said UCF needed wide receivers a corner, a right tackle, and probably another safety. I agree.