It’s been a momentous week for the Transformers franchise. So is there going to be a Transformers 4 or a reboot? And what can we expect from it?

A couple of days ago Transformers: Dark of the Moon reached $1 billion worldwide gross. That’s $338 million in the US and $663 million internationally. Incredibly it’s the first billion dollar grossing movie in Paramount’s 99 year history. And it’s one of the 10 highest grossing films worldwide of all time. This was no doubt helped by the inflated ticket price of 3D, but still it’s a great achievement, especially coming off the back of a generally disliked second movie.

So what happens now? Shia LaBeouf and Michael Bay have had enough. Shia told MTV “I’m not coming back to do another one. I don’t think Mike [Bay] will either,” the actor continued. “It is still a hot property I think, especially coming out of the third one. So I imagine they’ll reboot it at some point with someone else.” Bay wrote on his site, “I’m kind of sad to leave the franchise.”

It’s a common Hollywood tactic to pretend you want to leave a successful franchise just to boost your next payday. But after five years of Transformers blue-screen filmmaking and more money than they could ever spend, it could well be genuine.

If they do go, will it mean a reboot like Shia suggests? No. The producer has stated “Certainly not a reboot. We haven’t lost the Transformers. They didn’t grow up or become expensive like Tobey Maguire. I’m pretty sure there will be a second trilogy. I am pretty sure it will kick ass. And I am pretty sure some of you will hate it because it wasn’t all bots.”

There have been rumours that Spielberg might direct or that Jason Statham might be the new leading man (he’s dating Rosie Huntington-Whiteley in real life), but trust me those will prove to be nonsense. Bay himself has said the Statham thing is untrue.

TRANSFORMERS 3 SPOILERS: One problem Transformers 4 will have is how to deal with the bridges burnt by Bay at the end of Dark of the Moon. Killing Starscream and Megatron in such a final way means there’s going to be a huge gap in future movies. Then again, could Megatron somehow be recovered enough to become Galvatron (the ‘re-born’ form of a destroyed Megatron)? And were they both fairly minor players in Dark of the Moon anyway?

Bay said he wasn’t keen on the Dinobots, but if he’s exiting then this would seem the time. They’re great characters, would present a fresh new spectacle on screen (giant metal dinosaurs trashing a city), and their prehistoric-form would offer some obvious plot opportunies if it meant prehistoric-origins too. The series sure does love to show the Transformers dropping in on earth’s history.

Unicron (the planet-sized Transformer from the original animated movie) is the villain most fans want to see. While this would be jaw-droppingly spectacular, it does present a huge logistical problem – how is Shia LaBeouf’s human replacement going to battle something the size of a planet?

Update: (February 2012) Michael Bay has been persuaded to stay on for a fourth movie. Shia is gone. Transformers 4 will replace all the human chracters with an entirely new cast. They haven’t decided yet how they are going to handle the robots – they may reboot them too, they may not. The release date is summer 2014.

Update: (November 2012) Mark Wahlberg has been confirmed as the new star, replacing Shia LaBeouf.

What do you want to see happen in Transformers 4? Should Michael Bay direct? Which new characters do you want to see? Leave your plot ideas in the comments.

Sources: Independent, Digital Spy, TFW2005, ShootForTheEdit