Jetfire and Sentinel Prime the noted traitors to their factions. What drove them to do so? Jetfire is an ancient Seeker. Tired of being a Decepticon. Part his motivation for betraying the Decepticons was he was abandoned to die on Earth. Another part of his motivation was being idealistic of an age well before he was created. Where the Dynasty of Primes led a benevolent empire. He got tired of all the chaotic destructive tendencies of his fellow Decepticons. Making him a noble demon. Renouncing his Decepticon heritage declaring himself an Autobot. Inspiring even Wheelie to do so. Jetfire sacrifices his life as he sees it as redemption for being a Decepticon all his life. Sentinel Prime betrayed his own principles to save the world he loves. Even if it means enslaving the race his ancestors protected and taking over the Decepticons to do it. One can say Sentinel has a messiah complex. He saved his race before from self destruction and aims to do so again. Though he has regrets and doesn't feel worthy of the Matrix of Leadership. At first he couldn't kill Optimus Prime who is his last of kin. But even Optimus he will destroy if he got in the way of his desire to rescue Cybertron. Indeed the difference lies between the two is that one sought to save his soul while the other sold his soul to save his world and those that he loves.
I like the thinking. I had more of a struggle liking Sentinel though throughout the film. He was a bit of a stuck up twat really, he didn't have the grace Optimus did. You could say he was less of a bots bot then Op was.
Well he and Optimus were royalty. I took the whole gods on Cybertron line as a reference to the Dynasty of Primes.