I agree that the 49ers defense is very athletic and fast but wouldn't that partially be why you would use a read option? You will force them to stay in their blocks and lanes and not cheat. One DB should be "frozen" until he knows where the play is going having to account for RW possibly running.
I think if done right you can use it against most any team especially those that otherwise would put a lot of pressure on the qb
The read option is most effective against slower undisciplined defenses, that way there are lots of mistakes and plays where they can't catch up to the QB or RB once the wrong gap is chosen. Just not sure SF's defense fits that scheme.
But having said this, SF's defense is just plain good, so it's not like you're going to expose them in some way, shape or fashion........your entire offensive game plan has to be solid. The good news is now that Wilson has a great command of the playbook, we can throw the entire kitchen sink at SF.....and not just the basic plays we were calling first time around.