Something that was mentioned in the live Q&A the other night was about the character Cogman, which could be another red herring by Michael Bay so that it doesn't spoil the surprise (like saying that Megatron was not returning for TF2)... so true or not, it is a spoiler either way.

Don't read on, if for some reason you were already looking at this spoiler-filled topic and don't want to be spoiled.

Many are already aware from a recent media release... and the reveal of the Deluxe toy... Cogman is a Head/Titanmaster.
Michael Bay mentioned this again in the Q&A, but told the audience that he wanted him to actually fulfil his original gimmick, to rip off the head of another bot and take control of its body (like the Japanese Godmasters taking control of lifeless robot bodies).
Now, this could still actually happen in the movie, and he's just trying to seed a little doubt to anyone who already read about that gimmick in the recent press release. But in case it really was cut due to budget (as he claims), it wouldn't be the first time a Hasbro toy or gimmick was released that didn't end up in it's corresponding movie. The first movie was originally supposed to have Wreckage and Arcee, while TF2 was meant to have the three Arcee bikes combine into one robot, but since the toys take longer to produce than the amount of time it takes to film and generate CGI in post production, the concepts in the original script and promo/concept art were started by the toy designers long before it was changed by Michael Bay. And by the time something is changed during filming and post-production (like Optimus's sword in the first movie), it's too late to change it in the first release of that toy.
So if this story is true, the Cogman and Nitro toys will have a gimmick that was supposed to be in the movie (Nitro's head on the Deluxe toy can be removed and replaced with Cogmans... but Nitro's head isn't a Titanmaster). And it would be a shame, as it would be a wasted gimmick that may not be easy to explain on the toys (at least for Nitro - a toy that is said to have a removable/retractable head that won't make much sense if it isn't in the movie... to give kids and collectors a movie scene to play out).