Now, take a look at Garoppolo: He likewise has no predictable physical weaknesses. His arm is adequate. His release is lightning fast, maybe the fastest in the NFL. He doesn't need to set his feet to throw, and he's very quick at going from recognizing the time to throw and making the throw. So, there is nothing physical that a defense can key on (unlike with Kaepernick). That leaves only the possibility of finding some tendency for him regarding throwing the ball, but he's thrown it all over the field his entire career and in college. He is not predictable in where he throws, in particular because he doesn't need to see the WR open before he throws it.
He HAS a weakness, however, which was obvious from the beginning, and it's a potentially crippling one: he takes chances with the ball, just like Favre, except his arm isn't nearly as strong. This weakness will haunt him in the future. However, the key here is that it is an UNPREDICTABLE weakness. No one can anticipate when Jimmy G is going to try to thread the needle into a place he has no business attempting a pass.
The only other possibility for your post to be accurate is if Jimmy G somehow telegraphs where he's going to go with the ball based on a certain coverage or read. However, because of his absurdly fast release, even if he did, defenses will not be able to capitalize on it. Instead, the only predictable weakness defenses will be able to exploit are SCHEME weaknesses (like what the Patriots did to Seattle in the Super Bowl based on the formation at the goal line on the INT to Butler). Say, for example, if the 49ers always run a slant out of stacked/staggered formations (something Shanahan has always liked doing). Then a defender could anticipate the throw before his arm is even cocked, and then get an INT. But all that would result in is an offensive adjustment by Shanahan.
