Agree on this I thought it was a bit dumb.
Iron Man's old suit could toe it with THOR (if only for a few minutes) yet they get smashed up easily by extremis thugs. Minor complaint though.
I know that they have to make things dangerous for the hero for the climax, but damn it felt like the suits were made of paper.
However, I really loved that we got way more Tony Stark outside the suit action scenes. They really stepped up in the action department for IM3.