I personally think Starscream could be just as good a leader as Megatron is, if not better. I was re-watching G1 and I noticed that quite a few times, Megatron's plans would fail because he didn't listen to Starscream. Starscream would be like "d00d Megs, this stuff is too unstable you can't use it" and Megatron would say "Cool story bro." and ignore him. Starscream has proven to be almost as strong as Optimus in a fight so he has the strength. He has the strength, he has the intelligence, he has the speed... Some people say Starscream is a coward, the ONLY time I remember Starscream acting like a coward is when Megatron beats him up. Also, Megatron is incredibly stubborn, and sticks with his plans until his device is destroyed or whatever, while Starscream is smarter, so he would abandon as soon as he knew he couldn't win. Also notice Starscream's leadership skills. When Megatron is taken down and Starscream says "Decepticons! Follow me!" or something similar, the Decepticons follow Starscream with absolutely no hesitation. So, that is why I think Starscream could be a better leader than Megatron.