2. The Cannibals
For me at least, the best storyline in The Walking Dead is The Hunters. It had everything major character deaths, tension, gore and a threat bigger than Zombies. When the hunters are introduced in the comics we immediately know that there's trouble ahead for our survivors. This is a new threat, a smart threat. When you're focused on defending yourself against Zombies, you don't want to think about having to defend yourself against other humans, particularly ones armed with sniper rifles and a penchant for human flesh. The cannibals are responsible for the death of Dale in the comics, and whilst he is obviously dead in the TV series already, there's still a chance the writer's may be looking for a way to get rid of some of the other supporting cast members. This could be a way for them. Whilst no doubt a dark storyline, The Walking Dead series has never been shy of getting a little heavy. Introducing the cannibals would be a great new threat for Rick, and is certainly something that could be introduced after the fall of the prison, or perhaps even as a sub-plot for some of the supporting cast to get involved in this season. With The Governor currently MIA, it may be the perfect time to bring in the cannibals.