I absolutely loved the movie myself.
I did feel there were places that needed more character development however. And the couple of slow downs and the "love story" that could've been done without.
I completely hated that throughout almost the entire movie there were no Decepticons with the exception of Barricade and Frenzy, then suddenly they come out of the woodworks. Yes you see Blackout early, and a Scorponok who should in theory still be alive, albeit damaged. But there were many more Transformers who needed more story IMO.
I too was sorely disappointed when Jazz was ripped in half without so much as even a grunt of effort on Megatron's part. It was almost as if Jazz was a petty weakling with no real strength to speak of. I did enjoy the way he transformed though, I thought that was cool. Up until the end he was probably my favorite Autobot, being a Solstice withstanding. I think Ironhide was a comedic sidekick he wasn't the "weapons master" as he was introduced, he wasn't a bodyguard as he was in the original series he was there for comedy and his lines and voice revealed that. Ratchet looked good. His face even looked good, he needed more lines.
I still think it's the best movie I've seen this year, and it will blow up big in this years box office. I am very interested to see the sequels now, and kind of hoping that Bay does not get signed on for the others just so we can get some more Transformer development.