I agree with you that members of Congress could do worse than read what Petraeus said on the Hugh Hewitt show. I'm intrigued by your strong recommendation, however. As at least a couple of bloggers have pointed out so far (Yglesias and Zengerle), Petraeus was really quite careful not to back some of Hewitt's wilder (in my opinion) views about the need to take the war to Iran, the press's alleged ignoring of good news, etc. Instapundit has become associated, fairly or not, with a pretty uncomplicatedly hawkish position on Iraq and the GWOT generally. Are you telling us you accept Petraeus's nuances?
Or at least defer to them. I'm not qualified to say whether Petraeus is right or wrong about all the details, but clearly members of Congress would do better listening to him in detail than to other people who know much less about the facts on the ground.
I don't know what "uncomplicatedly hawkish" means, exactly: I want us to win, and I don't have much patience with people who clearly put their domestic political agendas ahead of winning. If that's "uncomplicatedly hawkish," then I suggest we could use more of it.