I've written all this before. I watched Manuel at FSU. He gets blamed for some things that really should be on his receivers. The FSU offense is perceived by some as simple. Perhaps it is in it's design but not in it's execution, especially for young receivers. That offense is a limited number of plays run out of multiple formations. If a receiver is in the wrong place it can make a QB look indecisive or inaccurate. Manuel also did not have a very good relationship with Jimbo Fisher.
As to Manuel's current play, he is thinking too much. He seems to be so concerned about making a mistake, he is overly cautious,. He also aims the ball at times instead of just throwing it. When he is in a two minute drive he is at his best because he just plays. He did that on Sunday and in the first preseason game. To be able to run the two minute drill is a great quality that some QBs never get. As to the rest of his game, I believe it will come in time, as his confidence builds, the game will slow down and he gets to know his receivers better.