Yes Action is a genre but Transformers if FAR from the definition of this genre. Terminator, Die Hard for example is testament to the fact how action should be (entertaining and clever) <-- we're not expecting much? I doubt Bay is a fan and I seriously doubt he cares about TF fans and what they think. However, he is smart enough to realize that he needs a hit. 'The Island' was a colossal bust. Two bombs in a row would not bode well for his career, especially one with a budget this large and with Spielberg ties to the project. Even if he doesn't care about TF's, he will care enough to look out for his own best interests which in the end will hopefully lead to the movie being well-done. And as it has been stated 100 times already....HE DOES NOT WRITE THE STORY...which is the most important part. (that's your answer to "grossed 1 billion").

Now for why people criticize Michael Bay. I'll give him some credit, he's just a director and has already been given a crappy story to work with so he can only do so much. His technicality for film-making is just downright shoddy. Bay also can’t keep a camera still to save his life. Slow motion is so incredibly overused as if he's telling us – “This shot is really awesome and you should love it too!” Yes, Bay focuses more on action than he does on the actual plot of the film. And he hardly ever does more than one or two takes of close-up’s on actors in important plot points but is that how Die Hard was? No. Is that what "action movies" are supposed to be like? No.

South Park explains it best IMO - http://www.youtube.com/watch?v=EeSUuj98Rx0