You know, until I looked it up on TFWiki, I thought Sideways WAS Barricade. Since both Starscream and Scorponok came back, I thought it was the writers being thorough with loose ends, since those three were the only surviving Decepticons from TF07. Obviously I was wrong, both about Barricade and the writers being thorough.   Not to mention that I had forgotten that Dispensor, the XBox 360 and the Cadillac Escalade also survived.

On a related subject, which Deceps are left to return in 2011? There's Megatron and Starscream, obviously. Soundwave was never shown coming down to Earth, so he's probably not dead. The Doctor disappeared, so he could easily be alive. Reedman may or may not be alive, depending on whether or not he was inside Ravage when Bumblebee showed the audience how to skin a cat. I think that's about it. Devastator could easily be resurrected, but I think it's obvious from RotF alone that he's supposed to be dead.

Of course, I'm going from the films alone. The comics have shown that Barricade, Dispensor, the XBox 360, and the Doctor are all dead, but I wouldn't count on the movies honoring this.