http://www.nfl.com/videos/kansas-cit...s-on-the-field
This video explains the #1 issue with Alex. Casserly basically says that if Pittsburgh's defense gives the same opportunities and looks to Brady as they did to Smith, they will be torched. And he is damn right.
Alex leaves too many plays to be had. That is the issue with him. He's not bad, in fact you could argue he's pretty good, but a playmaking QB would never leave the amount of TDs off the board that Smith does. Insert QBOTF.