#1 Should not win: Roman Reigns
A recent report indicated that Roman Reigns is the front runner to win the Royal Rumble match next year. While a Royal Rumble victory will allow 'The Big Dog' to return to the main event picture, fans might turn on him again, knowing how he has been pushed in the past few years, especially during WrestleMania.
After receiving a huge push, Roman Reigns became the face of WWE, replacing sixteen-time WWE Champion, John Cena. From main-eventing four WrestleMania events in a row, to pinning The Undertaker at the Show of Shows, Reigns has accomplished just about everything there is to accomplish in WWE. Nevertheless, he hasn't been 'the guy' after returning from illness earlier this year.
Reigns already lost two matches against Baron Corbin, which is uncommon. Therefore, he needs to win some big matches before getting a title shot for the Universal Championship. Moreover, Reigns already won the Royal Rumble in 2015, which wasn't received well by the WWE Universe. Reigns could certainly chase the Universal Title, but winning the Royal Rumble isn't a prerequisite.