So far we have learned that Tyrese Gibson, who played Robert Epps in the first 3 Transformers films will be up to reprising his role in the fourth film despite Michael Bay's decision of having the entire human cast replaced. Gibson's chances of return will depend whether the fourth film will continue the story from Dark of the Moon or not. If so, his character Robert Epps may turn up as the main human protagonist since Labeouf is not coming back.
Hopefully if Michael Bay does make Transformers 4 a definate and absolute sequel to Transformers Dark of the Moon and NOT some god damn waste of a lousy prequel which would make our wait a waste, the main villain will hopefully be a decepticon and not Unicron or some other autobot traitor like Sentinel Prime who ruined most of the amusement for the audiance as a complete setback of a disappointment in Dark of the Moon. Also I am sure that most of you among many Transformers fans are demanding to know just what the hell specifically made Sentinel Prime betray his autobot comrades over a dying planet when he knew that everything he did was wrong and against everything he stands for. Believe me, I don't take "survival of our race" for an excuse. Before he was executed, he seems to still be on the right path just when he was about to explain to Optimus why he had to betray him. It sounded like he was trying to prevent the decepticons from doing something that would cost him and the autobots their victory in the war. Too bad we never found out what that specific reason was because Optimus was pissed with Sentinel for not listening to him on what he was suppose to stand for as former leader of the autobots and because of every awful word he said that made him a nightmare to Optimus and because of the massacre in Chicago and for every awful everything he did to make himself a disgraceful monster of an autobot to the humans, Optimus executed him just to save the aubots reputation of the humans and to prove that they are nothing like Sentinel.
Hopefully if Michael Bay does have any honesty and heart of good and understanding left in him, he would indeed bring Sentinel back in the 4th film as a reformed character, who will make up for the wrongs he did by helping the autobots and the human forces deal with the decepticons they are about to go up against. Maybe even the ones that were incharge of having some of the humans enslaved during the Space Race of 1961 as well.
Surely you all saw the Wreckers in the 3rd film, so let's go with the Predators. Not to be confused with the Predacons, the Predators are a group of decepticons that are led by Skyquake. Skyquake is a really tough and merceless decepticon. So if there is any decepticon worthy enough to appear as the main villain in Transformers 4, it's Skyquake!
If Skyquake does appear as the main villain, he and every other decepticon under his command will plan their revenge against every human soldier on the planet for wiping out many of their comrads in the previous films by any means necessary. The best aircraft for this decepticon to transform into should be a B1 Lancer/Bomber Jet and as a bomber jet, he would go drop a ton of bombs on a N.E.S.T. team that is hunting down one of his fellow decepticons at the begining of the movie before confronting Optimus Prime and explaining to him about the events from Dark of the Moon.
In Transformers Prime, Skyquake was one of the first decepticons on Earth who was revived by Starscream with an energon cube, which means that if another fragment of the allspark revives Skyquake, it may charge up the weapons, ammunition, and explosives with its power. It could also give Skyquake the opertunity to use the bombs that were charged up with the allsparks power to bring every vehicle and aircraft to life within aa 5 mile radius in any military vicinity and have them target every human soldier that is there along with others that are involve.
If so, Skyquake will do it not just by traveling over the globe to launch the bombs but by using space bridge pillars to open up a portal for them to launch them through. Surely Sentinel Prime said that the pillars were his design, but what if he was lying? In Transformers Prime, Ratchet said that the decepticons were the genius' at building space bridges, so it is possible that Skyquake and the Predators were the ones who designed the pillars. When using the pillars, it taks 5 to transport anything that fits through the portal from one planet to another, but with two pillars, they would open up a portal to anywhere on the planet just by remote control.
This method is called Operation Typticon; a plan of attack the decepticons might have used to infiltrate well defended autobot cities on Cybertron and then target the main base with their ultimate weapon, Trypticon himself! This is probably will be what Sentinel Prime was trying to prevent from happening that it is possibly the source to his beliefs of why he thought and said to the autobots that they were never going to win the war right before he killed Ironhide at the gate to the Nest base he attacked. He probably witnessed it before making the deal with Megatron.
Once Skyquake and the decepticons recommence Operation Trypticon, they won't be targeting the autobots. This time, they will be targeting every military base within the United States and instead of sending troops to infiltrate, they will be using the bombs that were energized by the allspark fragment inside Skyquake and throw the bombs through the space bridge into the military vicinity, bringing every military vehicle caught in the range of the bombs' shockwaves to life as Combaticons and having them execute every human soldier in the area for the decepticons themselves. Skyquake will do it to correct Megatron's mistake of having Sentinel Prime collaborate with them and to turn Earth into a new Cybertron. Also, Skyquake will be sure to prevent Optimus Prime and his crew of autobots from finding him. He will be sure not to have any decepticons harm any innocent humans on the planet, knowing that they are not a threat to them like the military and he and Predators will have plenty of other surprises for the autobots as well.
And who would be the best actor to voice the decepticon Skyquake than the famous SCI Fi actor Lance Henriksen himself.
Lance Henriksen is most popular for his appearance in the movie Aliens and he voiced the decepticon bounty hunter Lockdown in Transformers Animated. His deep and dark voice should be effective enough to voice Skyquake for sure!
In the mean time here is a concept art of what Skyquake may look like if he appears in the 4th film.
Be sure to keep your eyes out for more information on the movie when hit hits theaters in 2014 on the franchises 30th year!