The best thing about the show is the intelligent writing. The character of Shane is very impressive. They could have just written him off as another macho, hot-headed militant, and treated him, at best, as a necessary evil.
Instead, they place him in pivotal roles in actions that appear unethical to some of the other characters, but instead come off as morally ambiguous to more open-minded viewers: For example, his sabotage of Otis and subsequent sacrifice of him, so that he could ensure getting back to the boy and save his life. Also, his empowering of the blond woman (the one who lost her sister) which enabled her to cope and survive quite handily.
They even had him comforting the mother who just saw her zombified daughter killed. That was touching, no?
When Shane confronted Dale in the woods after he was trying to hide all the firearms, the old man tells him-- "you are made for this world." Well, yes, he is. And isn't your group better for it? There was almost a hint of envy coming from the busybody old man as he delivered the line. And I like Dale's character, too.
The first season was all about action and gore-- typical zombie fare. But now we are left with the only place this can go, which is the ponderous and tragic realization that things are just awful, and doom surrounds them all. The show has become very heavy, as it should.
Edited to add: the only thing puzzling is the character of the black guy. His continued irrelevance sticks out like a sore thumb.