It's PAINFULLY obvious what would have happened if Optimus had not died in the animated movie and I don't expect this comic to deviate from that:

*Optimus kills Megatron. Has a realization "Holy s**t! I've been fighting this guy for 9 millions years and I killed him! I finally f***ing killed him"
*Unicron shows up. Optimus - full of vim and vigour from killing his arch enemy simply flies down Unicrons maw, opens the matrix and destroys him.
*Optimus has another realization "Holy fraggin s**t! I killed a god! I killed a f***king god! I'm awesome!"
*Optimus then goes around killing all the Decepticon leaders - Shockwave, Starscream, Soundwave etc. All the remaining Decepticons go into hiding or run like hell!
*Optimus decides that now the Cybertronian Wars are over and he is so cool that he better go from planet to planet making sure that "Freedom is the right of all sentient beings" and slagging the crap out of any planetary government (including Earths) that doesn't fully practice it. Puts Autobots in charge of the planets to maintain the 'freedom'.
*The Universe finally free (under his control) Optimus gets bored. Marries Elita-1, gets bored, cheats on her with Arcee. Argues that if he can kill fricken gods and 'free' the universe he can do whatever - and whoever - the hell he likes!
*Now divorced Optimus demands a bride from each 'liberated' planet. To make sure they are compatible with his biology he has each alien bride retrofitted to be half femmebot.
*Gets bored again, finds the core of Primus within Cybertron. Merges with it, takes it over, mechaforms Cybertron into a giant celestial body for himself.
*Spends the next few million years floating through space in his planet sized body while his millions of alien-femmebot hybrid wives live on his surface and spend all day every day giving every inch of him a damn good buffing and spit polish.

I mean, c'mon people, who didn't see that ending coming eh?