How it should have ended
Pillars? Yes the pillars were important... but not the most important in his plan. He knew what would happen if the Autobots and Decepticons kept killing each other. Cybertron was already lost when he took off for his final flight – lost, but not beyond repair. He headed for Earth, the planet of hidden Cybertronian treasures. The Tomb of Primes was here, with the Matrix of Leadership possibly still hidden inside the protective shell formed by his predecessors. It's the only tool that could power up a sun harvester - and one of the few that could bring dead Cybertronians back to life. He would've bet the Allspark came in this direction too. And, if the Allspark came, so did its pursuer Megatron.
The Matrix. The Matrix of Leadership. Here, right in his chest, powering up his Spark.
Optimus Prime. The greatest Transformer there were of all time.
Earth. Then it means he arrived at his destination, finally. The Allspark and Megatron may be around too.
Time to calm down. One step back. Optimus – check. Matrix – check. Earth – check.
Well he cannot ask directly if Megatron was here too, now can he. But he can ask if the war was still on.
The news he gets felt like a blast in his Spark. Cybertron being a barren wasteland. Autobots living as exiles, hiding among primitive arrogant lifeforms. But if five pillars survived the crash, so did the other hundreds of them. And if the Autobots have no knowledge of them, they must be in Decepticon hands.
Pillars – check. Decepticons – check.
With so much lost to the war, both factions must see by now where destruction leads. Megatron might be a tyrant but he's never been an idiot. He may have already realised that the only way out is a truce.
Everything's set. With the pillars, they can either move the sun harvester or build a new one anywhere. With the Matrix, they can use its power wisely. With both Optimus and Megatron supporting him, they can finally come to an agreement.
Now it's his turn: to get the two leaders cooperate before they would cause even more damage.