well, it's not quite like that
well, I liked the movies, but because I see them for what they are, a real life version of the cartoons, which if you remember, were very simplistic, I think everyone now things movies have got to have amazing plots, subplots, great dialog, etc, if you watch the cartoons, you'll find the movies are just like that, but in real life, with better graphics. I'm sure if I gave you yourself a pen and paper and told you to write a movie about robots, you'd come up with something just as good, so it's not like what they've done is goundbreaking, I dont mean that to insult you either, just that, it's very simplistic and for people who don't expect much, it works.
as for megan fox, she did have and was of critical importance, but for one important fact, most of the "kids" they were trying to bring into the movie weren't born when transformers was on TV, or were so young, didnt have any connection with it, megan's job was to make all of those kids who might not go to watch it because it's about stupid robots and not about men with guns, is to get their dicks hard so they rush the cinema when it comes out.
mission successful I think? but thats the only reason I can think she was in the film to begin with