According to Hasbro President Brian Goldner, that's the plan anyway. He also confirms that the film is set for a 2014 release. Click for the details, as well as a "Placeholder Logo" for the movie..
Hasbro President Brian Goldner was on hand at the UBS Best Of Americas 2012 Conference today to discuss plans for the upcoming fourth installment in the lucrative Transformers franchise. Well, lucrative that is from a box office standpoint, but there is one area that Transformers: Dark Of The Moon apparently disappointed in - toy sales. You see, because the third movie used basically the same cast of Autobots and Decepticons as the previous movie did, toy sales dropped. No new Transformers, no new Transformers toys for the kiddies. According to Goldner, for this reason "Transformers 4 will have a new cast of [robot] characters and it will be a story revolving around these new characters.". New characters created for the movie, or new characters from the current Transformers canon that we haven't seen yet? It's not clear, but I wouldn't bet against the former. Goldner doesn't mention Michael Bay, but he is still apparently set to helm the fourth installment.
So how does the prospect of no Optimus Prime or Bumblebee in the next movie sit with you guys? Personally, at this stage I couldn't care less if they replaced them all with Teletubbies.