We have previously reported that Transformers: Age of Extinction was not as big of a hit as its three predecessors, but Transformers 5 seems somewhat certain.  The release date is in question as well as the film's director Michael Bay, but there are a few things that we have heard about the cast, with some spoilers. 

First, there doesn't seem to be any confirmation on whether or not two major players would be returning.  The first would be Michael Bay, and some sources have stated that the director has divorced himself from the franchise.  In my opinion, trying to do a Transformers movie without Michael Bay is like trying to do a Jurassic Park movie without Steven Spielberg.  Yes, Spielberg did return to do The Lost World before other directors did the sequels, but The Lost World was not well-received, and this has been a criticism of Bay's later Transformers movies. 

It does sound like the second major player, Oscar Nominated actor Mark Wahlberg, will definitely be on board for the sequel, according to Enstarz.  Wahlberg has even commented on Michael Bay's current lack of involvement in saying: "I can't speak for Mr. Bay, but something tells me we'll be on the set soon". 

Unfortunately, if they don't get on the set as far as filming Transformers 5 is concerned, the film could be delayed.  We have reported before that the studio wants to put out a new Transformers movie every two years, which was the gap for the first three films.  A delay could move Transformers 5 release date from 2016 to 2017. 

As for as the plot goes, we have also reported on some sort of plot where Optimus Prime meets the creators of the Autobots and Decepticons in space, and this certainly seemed to be what Transformers 4 was leading up to when Optimus Prime just blasted off from Earth at the very end. 

Peter Cullen, the actor who provides Optimus Prime's trademark booming voice, has stated that "the Transformers movies are going into a darker area" and that perhaps "Transformers 5 and 6 will go back more to its roots".  The roots would be the animated show from the eighties, which was targeted to younger viewers in spite of its constant robot-on-robot violence.  Cullen talks about a certain line that he was supposed to say which he was uncomfortable with, according to MStarz.  Cullen does not say the line, but tells his audience at SacAnime 2015: "I think you all know what that line was". 

Another rumor about the plotline of Transformers 5 relates to the casting.  According to Enstars, Dwayne Johnson and Bruce Willis could be appearing in Transformers 5.  These two actors appeared together in G.I. Joe: Retribution, and their involvement in the next Transformers film could signal a crossover of the Transformers and G.I. Joe franchises, both owned by Hasbro.  This wouldn't be the first time that the two toy franchises have teamed up, as there was a short comic book series in the eighties distributed by Marvel that combined the two teams, and their enemies.  It looks like Hasbro is kind of stealing a page from the Marvel cinematic movie playbook if its movie properties of G.I. Joe and Transformers are planning to crossover. 

I would imagine that it will be made known when Transformers 5 begins filming, and hopefully it can meet its projected release date of summer 2016.