Optimus Prime: The Movie

If you do a Megatron movie, you should probably do an Optimus Prime movie too, right?  In the comics and TV shows, Optimus has a few different origins, but they all start out with a bot named Orion Pax.  In some Orion is a laborer.  In others he's an archivist.  And in more recent ones he's a cop.  I suppose the latter would be more exciting.

Basically the idea is Orion Pax is a good cop but sees corruption all around him, especially at higher levels.  And so when Megatron starts advocating for revolt, Orion actually agrees with him and joins the Decepticon cause.  But where he and Megatron differ is how to achieve their goals.  Megatron of course believes in violence and killing and tyranny.  Orion prefers more of the Gandhi or MLK Jr nonviolent approach and then letting the people of Cybertron decide.

They work together at first but when Megatron's second revolt begins and starts killing those in charge, Orion has to stand up and fight back along with other Autobots like Prowl, Sideswipe, Ratchet, Ironhide, and his girlfriend Elita-1.  And then the leader of Cybertron dies and the Matrix goes to Orion, who becomes Optimus Prime and vows to stop Megatron--no matter the cost.

Or something like that.