Looking at season one overall, it's very okay. Shooting on 16mm film gives the show a great look, and the sound design (especially during eerie quiet moments) is top notch. I also appreciate that AMC doesn't skimp out on the gore. In addition, I like that the actual zombie scenes have been kept to a minimum and not front-loaded during the first season. The best zombie stories are never truly about the undead but how the characters react and survive.
The biggest problem has been the writing. More specifically, the show really needs to have a point. A goal for the characters to achieve or at least obstacles that enlighten them somehow. The trip back into Atlanta and reaching the CDC fill up time, but what have we learned more about the zombie situation? Not much. If the show is just going to keep having the group reach a destination, settle, and then quickly get outta there, it's going to get old. Wandering around is fine for the first few episodes when trying to establish the ground rules, but it's gonna be repetitive FAST. Have them try to restart a community or something that seems like a definitive goal in mind.
Still, many great TV shows had a fine first season, only to catch fire creatively in later seasons. I'll wait and see.