3. The Death Was Handled Improperly
When a show kills a main character, there has to be three factors at play for the death to mean anything to the show: there has to be a good reason, it needs to be taken seriously (or not) and their death needs enough time to sink into the audience's minds. If the show really wanted to kill Brian off, they could have at least killed him off with a better reason than "shaking things up" in the writer's room. They could have made it into a story about a family grieving over a lost friend and finding their way out of the despair that comes with losing a pet. However, this is Family Guy, and as such nothing can be taken seriously without being followed up by a couple tasteless jokes afterwards. Brian's death was easily a two part episode,
at least. Part I, Steiwe and Brian properly start the time travel adventure from the beginning. Things go South, they change things back, and Stewie dismantles his machine. You end Part I with Brian getting hit by the car, and the family around him in the street. Part II, we open on the vet's office and get the sad news: Brian's a goner. We continue with the tearful farewell, and see Brian's death, followed by the funeral and some flashbacks of the family's various recollections of their favorite moments with him. We end the episode with a montage showing the passage of time, set to heartfelt music and showing The Griffins getting over Brian piece by piece. They arrive at the Pound to pick up a new dog, and lo and behold... here's Vinny! Credits and logos. See? Was that such a hard concept to think out correctly? Also, this two parter would have to be a season finale, just so the fans can absorb the fact that one of their favorite characters is no longer with us. It helps with the emotional blow, trust me.