Aww, I hadn't seen it yet, & you're the first person to tell me it wasn't good. I heard it was pretty good from some of my friends.
As I said, it's not very good. In terms of acting and storytelling, it could've been much better. However, for a movie based on GI JOE, a cartoon I really wasn't fond of to begin with, I actually enjoyed it. The action was good, the vehicles (the best part of GI JOE) were awesome, and it had a good plot.
But Transformers 2 was awful. The acting was terrible and annoying, the plot was non-existant and instead replaced with a disjointed series of events, and it's the only movie in my illustrious history of watching action/summer blockbusters flicks where I've said that there are too many explosions. As you said, it didn't have to be the Cartoon. Hell, it didn't even had to have a really great story, like GI JOE, or the numerous 80's action flicks of the past. But, it has to give me something besides 1 or 2 good CGI fight scenes and slo-mo Megan Fox tits.