- Motto: "Wait, we're supposed to save all humans? Are you sure?"
- Weapon: Energo-Sword
While Megatron did call for a truce at the end, I'm not sure how it would work exactly. I mean would Megatron still call for the human race to be slaves to fix Cybertron? Also, considering how vastly out numbered the Autobots are, wouldn't any truce be more like a formal surrender than actual truce? It goes against Prime's main goal which was to work with humanity to protect them from the Decepticons, which was the idea from the first movie.
Further more, if Prime had accepted, it doesn't mean that the rest of the planet would've followed suit. The relationship with the humans was all ready tenuous at best. If Optimus had accepted a truce with Megatron leading both forces, then the Autobots as a whole, would've been lumped in with the cons. At that point, if I was POTUS, my finger would've been the button (IE: Launching Nukes at Chicago[I would be more triggerhappy, than Triggerhappy]). So that's one reason for killing Megatron and Sentinel Prime.
The other? They started the war. A war which caused them to cripple Cybertron. In most cases, any Megatrons' post civil war plans always involve turing Cybertron into a mobile planetary fortress to be the heart of his intergalactic empire. I am going out on a limb and assume Movie Megatron's plans were the same. Also, Sentinel and Megatron share the view that all Transformers are gods compared to anything else. So even if a truce was made, I don't think either of them would've tolerated taking orders from humanity. Prime doesn't share that view at all. Even if Humanity hates his race, he still views it as a personal responsibility to protect them. Their (Megatron's and Prime's )ideologies are just too opposite from each other to be in a peacefully coexistence for anything longer than a short amount of time. Much like Magneto and Xavier.
On a personal level, Prime (I think) was too disgusted with them to even consider a truce. He just had to destroy his home world because of them, and their ambitions. There might've been a chance to someday work towards fixing Cybertron, but now thanks to them, not only are the Transformers nearly extinct, but any hope of restoring Cybertron looks to be over, finished. In Prime's mind, if Sentinel choose to reward the Autobots' faith in Sentinel, they might've been able to win the war with the space bridge tech, but he choose to betray them. Also Megatron's mad ambition had finally went too far. Everything Prime had ever believed in or cherished was destroyed by them. After millions of years of that, I would hate them more than anything for turning me into a warmonger by default and for damn near killing everyone I ever knew. He knows what happens when two Hitlers are allowed to live. Did they show remorse? Yes, but no amount remorse shown by them justifies their continued existence.
Also, after 27 years, it is great to see Prime end it.
Formerly Nova-Ting Ranger (That's right, I'm back! And in Pog form!)