Eh I dunno, I kinda liked Simpsons road rage, so hopefulyl a Family Guy game won't be crappy, and since Family Guy deals with more mature themes than The Simpsons (usually), they can go further with the content.
It might be a good game...Depends on who is making the game. If it's in the hands of a good video game making company, then chances are, it could be a good game. I thought the King Kong game would suck, but look how it turned out. It was probably that good because it was made by Ubisoft, and had some features that had also been used in games like "Prince of Persia".