The sub plots are sure dragging down the show. I really don't care for all of the emotional angst the female writers are dumping in the show. The confrontation with the wife over her pregnancy and her fling with Shane didn't track well at all. 
At least they explained WHY Hershal has the zombies in the barn. One is his wife and the other a son (stepson?) so he is obviously hoping that there will be a "cure" found. It is a case of losing his objectivity and failing to recognise that the walkers are no longer the folks they used to be and cannot ever come back. Hell, the decomposition should have made that a no brainer. Then again the fact that zombies are decomposing and still need to "feed" is somewhat contradictory in itself anyhow. 
How else are you to propagate the show, then?
Honestly, and hour of killing zombies week after week would bore me to death. I really don't mind the little side plots, especially the one's that explore the "what if" important questions of a post-zombie apocalypse world.
Food will be scarce.
Defensible shelter would be in demand.
The list of folks one could trust would be short, indeed.
Medical conditions will present themselves and will need to be addressed, including pregnancy.
Not everyone will have the same views on the morality of dispatching the zombies.
People are going to desperately defend what resources they have and will not be too willing to share.
When the trappings and conveniences of the modern world is stripped away, so will the veneer of civility with regard to humans start to crack and peel away, revealing everyone's true nature.
Most any society is roughly 7 meals away from anarchy.
These are the types of things not explored in a 2-hour George Romero flick (even though I love his work) and I am not embarrassed to admit that this is what keeps me interested. It dives into the normal questions not answered in your typical zombie horror flick.
