Re: "Only a Prime can defeat me" The Fallen Thread!
I think you guys are looking into this way to much, look not all the story has been written, thats why there will probably be spin-off books, a third movie etc...
Stop "being angry" at the plot holes, and start writing fan-fic on why they are the way they are.
My idea is that a Prime has a selflessness (like a green lantern has willpower) that gives him power, and to that extent I guess Greed? would be the other end which would also power them....hence the fallen being so strong.
Either way, I hope they do more on the fallen in the third one some how, and just have megs backstab him and be like GG NOOB