If it wasn't Megatron controlling Cybertron, it should've been someone else instead. I didn't like Beast Machines on how it went. Especially with Megatron using Optimal Optimus' body in the finale. What do you think how?
I would had loved to seen the G1 Predacons as the main threat. Razorclaw leading a Predacon uprising and overthrowing the Maximal leadership. Optimus Primal and his crew would had been caught up in an ongoing war on Cybertron. With his experience in the Beast Wars would had made him a great resistance commander for the Maximals.
Would've been kind of interesting had the Maximals returned to Cybertron to find that the Tripredacus Council had taken over Cybertron.
If Megatron had a brother, he would've took over Cybertron and locked him up beneath the council citadel. He'd be the one to have that disgust with organics. The Maximals find Megatron locked up in prison. They had no choice but to set him free and bring him to the Oracle. There can be a war between Megatron and his brother. One with machines ruling while the other side organics rule. But the Maximals are in the middle.
I liked how BWU did it. I hope Lord Imperious Delirious gets used as a villain more often. In my fanfic after the Maximals get back to Cybertron they and Megatron are arrested together with the Maximal and Predacon leadership by the civilian goverment. The Max and Pred leaders perish in an "accident" during transport to court. In Predacon prison Megatron gets a humbling lecture from a dying Kup who had made an assasination attempt on the head of goverment. Megatron inspires his fellow prisoners, takes over the prison he is held in and marches on the tri predacus council who is a puppet of the civillian goverment. They grant Primal amnesty if he agrees to lead a batallion against Megatron but Primal refuses. A former Decepticon hypnotizes Primal however and after this Primal agrees to the goverments terms, but once the opponents meet Primal manages to join his army to Megatrons. They start a campaign to "free" city after city, wich is jus what the goverment wanted, making use of growing tension to round up anyone with ties to former Autobots and Decepticons and secretly "dispose" of them. Megatrons army is more succesfull than they expected however as he manages to inspire Maximal and Predacon alike. Primal snaps out of his funk after an attack went wrong and leaves to find out why he was hypnotized and free the rest of his friends while Rhinox and Rattrap stay with Megatrons army.
Honestly, why not Starscream? His plot was unfinished in Beast Wars, so it would make some sense for him to make a reappearance. It could be he conquers Cybertron and tried to keep it technological, which actually makes sense since this is the Cybertron he always dreamed to conquer. Plus, Starscream.
I must be in the minority that thought Beast Machines Megatron was a great villain. Sure he was a lot darker and a lot less comical than the fanastic Beast Wars rendition, but defeat will do that to an egomaniac. This is the guy who broke every law he's ever known and traveled back into time with the least dependable crew ever and intended to destroy the timeline that led into his lifetime for just a chance at ruling Cybertron. His defeat was traumatizing. His ego literally couldn't handle it. It wasn't him who lost, his beast mode made him lose. He wasn't flawed. He was perfect and was tainted by the disease of organic matter. It wasn't him who was mad, the Maximals and Predacons were wrong for resisting him. Their free will was the problem, not his ambition. So he stole their souls and used their husks to build more drones to steal more souls to he could eat them and become God. Then as soon as he thought he had all but won he kept Optimus Primal alive just so he could gloat and "Yesss" in his face. He snapped right back into his Beast Wars personality as soon as he, in his view, had righted the wrong of his defeat. Sure, there's a little bit of fanon there bridging the gaps but it's the most compelling way to look at it, imo. Beast Era Megatron is unmatched as a villain, and his Beast Machines portrayal just makes him worse in the best possible way.
Because Starscream is a terrible villain who is incapable of conquering a turborat and is not actually a BW character. Honestly, why not Mindwipe though? He could hypnotize the governing bodies of Cybertron and rule Cybertron by proxy. The Maximals would never know who their real enemy was untill its too late. It would actually make sense since we know he is capable of pulling this off and having a beastmode he actually fits in in the show.