I think the press release gave a bigger spoiler than the Grimlock toy... which just sounds like a toy gimmick to me.
The Drift character is stated as (yet another) Autobot who was once a Decepticon... so could be a plot device in the movie, or maybe he's a double agent still working for the Decepticons.
For the first three movies, we basically had toys known of just about all the main robot characters from the preceding US Toyfair. And considering there are 8 or 9 different toy lines (regular and gimmick) this time, if there are more Decepticons in the 4th movie, I wonder if that means we aren't getting any (or many) toys for them. If so, it seems that each successive movie, we are getting more and more of the robot cast that are not being made as toys.
Mere movie merchandise I guess...
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