What He Was: When Family Guy first debuted, Peter Griffin was a rough amalgamation of Homer Simpson and Hank Hill. He was definitely dim and oafish, but he also exhibited a stronger conservative streak reminiscent of classic sitcom dads like Archie Bunker or Red Foreman. His stupidity and half-baked schemes were also a bit more grounded in reality, usually ending with him learning a real lesson by the time the credits would roll.
What He Is Now: Nowadays, Peter Griffin is basically Bugs Bunny. Per Family Guy canon, Peter meets the medical and legal requirements to be classified as mentally challenged, and he pretty much has a Deadpool-esque ability to do anything that he wants without fear of physical harm or repercussion, and he’s often fully aware of his existence as a TV character. It’s a far cry from the Peter Griffin we first met in the series, but his increased distance from reality has helped set Peter apart from other TV dads while also embodying Family Guy‘s kitchen sink approach to comedy.
What He Was: When Family Guy first debuted, one of the biggest distinctions between it other animated primetime offerings like The Simpsons was the presence of a talking dog. Brian Griffin initially served as an audience surrogate, not only by commenting on the surrounding debauchery, but also by providing Peter and others a voice of reason and guidance in times of crisis. Albeit with the occasional spurts of insanity thrown in for good measure, such as his brief cocaine addiction during his time as a K-9 unit.
What He Is Now: There is a strong case to be made that Brian’s transition over the years has been one of the more frustrating Family Guy evolutions to watch. The joke used to be that the dog happened to be the smartest and most level-headed member of the Griffin family, but now he’s more surly than erudite, and is often used as the unlikeable elitist liberal jerk who drinks too much and can’t keep a steady relationship. It has made for some good jokes, to be sure, but the also has (seemingly intentionally) made Brian somewhat less likable by making him more human.