With Megatron (maybe) not in the leadership role now, I think we could maybe see Starscream get his on screen shoot at leading. At least until Shockwave shows up. I may be wrong but with all the info in the comics that leads us to believe that Megs is for the moment not the big threat and Starscream seems to be Optimus's main priority... We could see Starscream leading. It would be cool to see him get his sidekicks Skywarp and Thundercracker too but we will see. Now I know there was the rumor that Screamer gets killed by a human character but im not buying it just yet. I really can see once Megs takes his leadership role back, it being Megs to be the one to kill Starscream. Also with Megatron on the run and (maybe) Starscream leading, I can see Soundwave maybe being the one to contact Shockwave and fill him in.