The only problem I have with a sequel is that the first season gets across the message of The Walking Dead quite succinctly - The Walking Dead is a zombie apocolypse where the survivors are more dangerous than the zombies.
I feel like another season might might live up to the first because of this. Remember, this isn't like a sequel to a regular game here. It's all about the story. Of course, you'd be crazy not to cash in on the phenomenal success of this game.