Why The Walking Dead Might Get Cancelled
1. Rick's Exit (And The Possibility Of More)
Andrew Lincoln might be on a one-man publicity campaign to tell everyone that honestly it's definitely going to even better when he leaves, it's hard to see how that can be the case. The Walking Dead is Rick's story more than anyone else's, no matter how many times he might have taken a backseat. He's the thrust of the show and it was through his eyes that we initially saw the fallout of the infection. Removing him is messing with the bones of the show in a way that most other shows that have gone the same way don't survive.
Removing Rick is like suggesting Breaking Bad could go on without Walter White, like Greys Anatomy could exist without Meredith Grey, that The Simpsons would be fine if the family moved out of Springfield and we just got a show about Millhouse instead. It didn't work for Scrubs, it didn't work for That 70s Show, ER began to fail when the main characters left and even The Office suffered when Steve Carrell left. Assuming it'll be fine here is ignoring the evidence.
Nobody can stand in for Rick (not even the beloved Daryl, who works best as a supporting character and who isn't relevant as much as he is cool) and if Danai Gurira ends up leaving because her MCU commitments propel her film career forward (which is very possible), the show will suffer once again. It's only a matter of time before there's a fatal blow.