Straight from the horse's mouth:
He throws so many things at you. There's not really a look that you see during the season that you haven't seen from him. So when you're able to go against it every day, it's a huge plus, a huge benefit. You might not realize it during that day, when you're getting beat up by it and everything like that. But in the long run, it really helps you out. He'll benefit from that.
One of the biggest fears about Sanchez is his lack of starts at USC. Games started has traditionally been a good indicator of NFL success in quarterbacks. One of my hopeful theories hinges on the talent level at USC. A lot of their backups were blue chip recruits. Perhaps Sanchez practicing against that kind of talent over the course of four years will help compensate for this lack of game experience. The Trojans are a championship caliber team and practice at a high intensity level.
It goes without saying practicing every day against a coach as creative as Ryan will serve Sanchez well. He will never see looks more bizarre than he will against his own defense.