That's what they said about Simpsons before they made Simposons: Hit and Run which turned out to be the most humorous games I've ever played.
Why should Family Guy be any different? At least it is consistent on the characters' main goals(Stewie's world domination, everyone making fun of Meg, Peter.... trying to.... well... do basically anything ect.). I think that a plot based on Stewie's world domination with different character's point of views would be pretty fun in a Family Guy world.
Sales bloke 1 :we need a new lisence
sb 2 :errrrr whats left
SB 1 :not mutch
SB 2 : Famly guy seems qutie popular with gamers
SB 1 : then we shall get the game rights to it and make any old 3d game out of it
SB 2 :but a 2d platformer on gba
SB 1 :This will be a hit