

First, He probably would probably make the choice not to look at the camera as much.
Second, he it would probably be more confusing if he did look at the camera as it would be harder to tell.
Third, being from old Hollywood he would most likely know that looking at the camera only once in awhile is the joke, not looking into the camera after every take.
Fifth, due to the new casting, people would not be in such a hurry to get Jim and Pam together, so the show could focus on what makes the show funny, Steve Carell and how working at an office can be funny.