Okay so I listened to the commentary here on Slate & I watched the movie last night. I think it's safe to say that I was one of those "hardcore" Transformer fans from the 80's - Yes, I was 12 yrs old when the toys arrived to store shelves and I even remember exactly when the first television episode came out.
So for this CG / live-action movie to arrive in theaters it (to me) is long overdue - my geeky friends and I have been waiting for this ...
There were a lot of gaps in the plot - many things were not explained. Yes, it was "totally" Armageddon meets War of the Worlds - but for us fanboys (and after the movie I literally felt embarrassed when I realized how many questions I was answering about the history of the transformers franchise mostly to the girls in our group who liked the movie but were utterly clueless about who was who and why things were happening) I think we were ready to forgive the many errors of "logic" that were evident in the flick. (it's based on a cartoon evetybody!!!)
In the weekly cartoon show from the Eighties there were often toon "glitches" like one transformers mouth moving while another's voice ran through a line of dialog AND let's keep in mind that logic to an 11 or 12 year old boy and a lover of Rockem' Sockem' Robots is still developing (and a bit skewed) so if you consider those facts then forward to 2007 ... lack of character background is forgivable mainly because if the entire 2 Hour 24 minutes were comprised of Fighting Robots and campy heroic dialog, I think even I would've walked out of the theater.
It's silly to expect a movie to answer all the questions we have - a little background work is necessary. Merely flipping the top of your head open and expecting to be force-fed all the unanswered 'juicy stuff' should never comprise the movie experience expectation.
Go find a fanboy, find a geek, get the 411 & then armed with that go see this movie again, preferably with a large group of your closest friends (hopefully one or two of those will be a Sci-Fi / Transformer geek) then thoroughly enjoy this movie!

Have fun ... and remember ... it's just a movie.

Autobots! Transform ... and Roll Out!