I thought he had the coolest look, plus the controversial history with both the decepticons and autobots. It could have been played up more. Plus, he had lots of potential storylines. Starscream's (ex) best friend, then to the autobots, then Megatron trying to get him back. In fact, I think Megatron would have made him his second over Starscream if he'd gotten his mitts on Skyfire. But after looking impressive in his debut, they kept neutralizing him in a lot of fights. I think they didn't want him to 'show up' Optimus Prime. Before Skylinks, he was the only autobot who could achieve orbital velocity and more. Shoot, they even downplayed his power after he was established. He would have made a great general over the aerial bots. Then he wasn't in the movie, and I have no idea what happened after that.