I'd like to see it called Fanboys 2: The Hunt for G1 Goodness
You could have a group of diehard G1 fans on a coast to coast road trip set in the fall of 2007, shortly after Transformers 1 was released on DVD and they announced that TF2 was going to be made. Their quest, to drive from somewhere on the east coast to Hollywood and convince Bay, Orci, and Kurtzman to use their treatment with tons of G1 references as the basis for the next movie. Hilarity insues as they travel the country in their beat up old red Volkswagen Vanagon, a G1 Iornhide.....

OK and for TF3 I would like to see:
LESS CRUDE HUMOR!! I was cringing a lot as I sat their with my 9 year old trying to share a very fond memory of my childhood with her. You can have many funny moments, but less of the sexual stuff in a movie that is in all reality a giant toy commercial!
Mirage, but as a NASCAR Sprint Cup car, which works assuming that GM will be involved with the 3rd one and they are obviously not going to pull out of NASCAR.
Hound. I really can't believe he hasn't made it in yet, maybe as a dune buggy, since a Jeep won't happen if GM is involved.
Starscream's armada, Durge, Ramjet, Thrust, Thundercracker, & Skywarp. I thought we were going to get it in TF2 in the previews where it shows the F-22's flying towards the pyramids, or when thy crashed into the carrier...but obviously we didn't.
Soundwave actually transforming with Laserbeak and Rumble.
Shockwave in any form.
The idea for the aircraft carrier transforming as Broadside, one of the G1 triple changers, or that could be Omega Supreme to battle some huge Decepticon combiner
Grimlock, if it can be done in a way that makes since in the confines of the "real" world
Blitzwing but with the Transformers Animated feel. I love that they gave him multiple personalities which made him my fave character of that series by far.