The biggest problem with the show is that it has to be a character-driven show, because there is basically no plot. They are just running from place to place trying to find a safe haven or cure. I understand that the graphic novel has been going on for some time and there is no end in sight, so it's not as if this is building any time soon into a "the gang finds a cure and the world is saved!"
Thus, for the show to work it has to develop the characters, make them interesting, flesh out their back stories, give them some interesting relationships, etc. To date, this has been a total failure. For example, I couldn't tell you the names of any characters other than Rick and Shane. Then there is Rick's wife and kid. The old guy with the RV. Short-round, the Asian. Sawyer with a crossbow. The hysterical blond who had one of the most cringeworthy scenes of all time with her sister last season. And the black guy. Oh, and the lady with the short hair.
Rick is the protagonist, but he's very flat. Sawyer w/ Crossbow is likeable, but a very cliched character archetype. The old guy is meh. Shane is annoying. Rick's wife is annoying. The hysterical blond is super annoying. The others are just kind of in the background.
That's not a real promising group of people around which to build a character-driven show. It doesn't help that the dialogue has been bad and the acting is weak.
The show has tense moments and there's obviously something there to keep me watching it so far, but the show's writers are going to have to figure something out fast or else this show is going to get very dull very soon.