I've been brainstorming, and well, I just had to see what some people thought of this.
The fanfic would start off pretty similar to G1, with the first chapter being set on Cybertron. Plenty of flashbacks: a few gladiatorial battles, the Decepticons' uprising, deaths of Sentinel Prime and Omega Prime (Yeah, RID reference.) Optimus Prime has just received the Matrix, and is new to the concept of being a leader. That was the only way I could stop him from being G1's Mr. Perfect.
Megatron leaves Cybertron with a group of "elite warriors" (who are, for the most part, incompetent morons), and Prime follows him. They crash on Earth (well, the 'Cons crash on the Moon), scan new altmodes, and start the war again.
And here's the main cast.
Autobots:
Optimus Prime: The new leader of the Autobots, successor to Omega Prime. New to the concept of being a leader. Thankfully, he manages to keep his cool in battles. Looks like his Armada incarnation.
Ironhide: Prime's second-in-command and weapons specialist. Looks like his G1 incarnation. (He even has the liquid nitrogen gun.)
Bumblebee: Resident kid-appeal character, with an unusual talent for sneaking around undetected.
Wheeljack: The group's mad scientist, who regularly comes up with wacky inventions that may or may not save the day.
Smokescreen: The slightly darker character of the group. Was once a brilliant thief and an escape artist, but eventually realized that crime didn't pay, and joined the Autobots.
Nightbeat: Brilliant detective, who often comes across Decepticon plots.
Roadbuster: In a slightly different universe, Roadbuster might've been a Decepticon. Thankfully, he isn't.
Cybertronian Autobots:
Ultra Magnus: Leader of the underground Autobot resistance movement.
Red Alert: Ultra Magnus's second-in-command. Makes sure the resistance hasn't been infiltrated by Shockwave's spies.
Brawn: Basically his G1 counterpart.
Cliffjumper: Basically his G1 counterpart.
Powerglide: Mainly sent on scouting missions, but he can fight if needed.
Decepticons:
Megatron: Brilliant military strategist, who prefers to work behind the scenes and leave the fighting to his minions. If you do end up fighting him, though, you probably won't survive. Cybertronian jet/Cybertronian artillery cannon triplechanger.
Starscream: Second-in-command of the Decepticon army. Usually ends up leading the Decepticons on their missions. Dreams of the day he can overthrow Megatron as Decepticon leader.
Motormaster: Motormaster is basically a big bully. With a sword.
Darkwing: Don't talk to Darkwing about life! He figures that if everything is pointless, depressing and eventually leads to a life of endless suffering, then he might as well make sure that others are getting it worse than he is. Looks like G2 Dreadwing, in G1 Darkwing colours.
Octane: Chronic fuel-hoarder. Really enjoys watching his comrades suffer from lack of energon. The only reason Megatron keeps him around is because he has a knack for finding new fuel sources.
Runabout: Comic relief. Looks like his G1 counterpart.
Runamuck: Comic relief. Looks like his G1 counterpart.
Laserbeak: The best spy in the Decepticon ranks. Fiercely loyal to Megatron, and will spy on anyone for him, be they Autobot or Decepticon. Nothing escapes his attention. Has been known to perch on Megatron's shoulder.
Devastator: Megatron's pet weapon of mass destruction. Looks like Movie Brawlastator, but coloured black and red.
Swindle: Has been known to sell Decepticon weapons to countries in the Middle East. Megatron keeps him around because of the potential international conflicts that he can start.
Scalpel: Basically the Doctor from ROTF.
Cybertronian Decepticons:
Shockwave: Ruler of Cybertron in Megatron's absence. Though he appears to be fiercely loyal to Megatron, he actually believes that he would be a better leader than Megatron, and plans to overthrow him in the future.
Gnaw: Shockwave's bodyguard. He has a tendency to get horribly mangled or suffer some other kind of seemingly lethal injury, only to survive.
Thrust: Aerial daredevil. The only thing he cares about is if the other Decepticons are amazed by his manuevers.
Vortex: Shockwave's chief interrogator and sniper. Fun fact: He likes bossing Ransack around.
Ransack: Comic relief. He also hates being a lackey for Vortex. Looks like his Cybertron counterpart.
Sunstorm: Basically G1 Sunstreaker. Egotistical, and obsessed with his paintjob.