Fiat justitia ruat caelum

Yes, that makes a lot of sense - I definitely see Starscream as ambitious, but rather afraid of actually succeeding. He's not ready for that and on some level he knows it. And while I generally think Megatron would probably rather his second-in-command be more respectful, there's no doubt that Starscream has his position for a reason. If loyalty was the highest value in the Decepticon ranks, Starscream would have been dead long ago. Though I disagree with it on some levels, I really liked the way All Hail Megatron portrayed the two of them - with Megatron pretty much grooming Starscream to succeed him, and berating him for the immaturity that keeps him from actually taking control. It's not quite how I usually see them, but it's one interpretation I find fascinating.