When Michael Bay decided to unleash the Transformers series on the world, everyone expected to see Optimus Prime, Bumblebee, Megatron, and Starscream. You can't give us a Hasbro toy and cartoon classic without making sure we see the characters that we've come to dig so much.
But what happens when you're Mr. Bay and you want to take the focus off the humans and put it where it belongs: on the ass kicking, building destroying robots? You introduce new bots. For the 4th release of Transformers (2007) we're gettin' some!
Hopefully Bay won't make the mistake of introducing twin characters that cause racial controversy. I have to say that was the most odd pair I'd ever seen and the weirdest thing to get upset about.
According to TFW2005 the president and CEO of Hasbro commented that there may have been a decent response to Dark of the Moon film, but the toy sales were a bit of a flop. In 2007, there was a focus on the vintage robot toys and bringing back that nostalgic feel. For marketing advantages and promotioal sales, they may be looking to do that again. Ah the world of advertising and dollar signs.