They'll definitely be better than last season... they have to be. Just getting McNabb instead of Campbell will help them immeasurably.
Still, I wouldn't get too excited about a victory over a team like Buffalo during the first preseason game.
I actually predicted that Shanahan would want to win this one decisively just to get his team off on a good foot. I knew he for sure didn't want to look bad against a very poor Bills team. That would have been disastrous for the morale of the fanbase and more importantly, his team.
Still, it is something to be glad of for the long suffering fanbase and you'd rather see a good win than a bad loss.
All will be settled when the real games start.