Isn't that the problem with every genre? That the following two genres:
Superhero movies: most have some villain with some "ultimate, master plan" to do something evil / never seen before, and the hero or heroes have to stop it. This film sub-genre rarely moves away from this long-worn template.
Police and/or government agency TV shows: Bad individual. Terrorist. Corruption from within. Serial killers. Regular character leaves or dies. Struggles with the restraints of the job when trying to solve/end crimes.
Largely, its all rinse and repeat. You can count on one hand the number of truly original ideas that have been introduced to TV or movies that have no parallels or influences from within or outside the genre. Success only comes from playing into the natural progression of the format, where the series cannot rest on the template, but treat characters like they are real people, with no cookie cutter, Saturday morning cartoon-like expected reactions. The Walking Dead is by no means perfect (the shock death matter is not among the series' finest plotting tools) but they have taken chances, and had character suffer numerous, sometimes permanent damages to relationships (usually their own fault), and the fact that the protagonists are not bulletproof, or capable of winning the day. TWD--despite its fantastic story--at least plays in a more realistic manner than many TV series and movies.