You're mostly right. Saying a QB is gonna be a bust because Russell and Couch flunked out is a weak line of reasoning. For every Russell, there's an Elway. For every Couch, there's an Eli/Peyton.
Mallet as a 1st rounder maybe, Luck certainly yes. Just my opinion, but I can't believe all the people who have been quick to throw Locker out the door, especially in favor of Mallet. The dude played on an absolutely horrible team and still registered his fair share of upsets throughout his career (USC twice, blew-out a 19th ranked Cal). He's played hurt this year, and while some of his games can't really be defended (Nebraska), he does the most with the least out of all the major QB prospects. I just wouldn't sleep on him if the Bill's were to trade out of the pick in the event Luck isn't available, or we win a few games and don't get a shot at the best DE, etc.