I think you fools are putting a little too much on this..
The Chargers have a gang of talent, and bringing in Norv Turner is not going to change that. They will be a good team regardless of who is running the show.
And yes it will hurt the Niners, but not as much as you might think. Sullivan (who many consider the leading candidate to take over the OC job) knows Norv's system and it has already been said they will continue using it. So the offense will not be learning a new system because that is what would have screwed them up. I believe they will continue to progress.