In a comment on my post about Optimum Cruise Speed, Gabe J (Check out his awesome blog here!) and I discussed changes over time in sitcoms (such as the appearance of Butters in South Park) and I wrote :
"I just watched the latest family guy episode, and rethinking of the first episodes, the whole show has drastically changed course and the characters have evolved much later than POCS or TOCS.".
The episode of Family Guy (FG) I was referring to was S10 E03 - "Screams of Silence : the Story of Brenda Q" that apparently got pretty controversial as you can see here.
Now I just watched the latest FG episode, "Back to the Pilot", it seems the creators wanted to show how much the series has changed. Brian and Stewie go back in time to the very first aired episode of FG and, to their surprise, everything is much different.