I rewatched the episode, it was better than the first time but I'm still not a fan, having the governor kill his own people was a cheap way to let Rick's group win a battle they shouldn't have been able to win without heavy losses. They also introduced new cannon fodder to be killed off during season 4.
Looking back the only main characters that died after season one were either irredeemable (Shane), wanted out of their contract (Dale), had to be removed due to the "only one black guy" rule (poor T-Dog) or were hated by big parts of the audience (Lori and Andrea). I don't think they'll dare killing likable characters out of the main group, they did it before they knew the show would be a success, never after it.
I predict that Rick, Daryl, Glenn, Maggie, Carol, Michonne, Beth and Herschel will survive season 4. Carl could die depending on the audience's reaction know that the primary hate targets are gone. Tyrese is as good as dead, he will be upgraded to series regular status next season, be awesome for a few episodes and then meet a horrible end to show that the show still dares to kill main characters.
In season 5 they'll feel compelled to kill one or two of the "safe" characters, so say goodbye to Beth and/or Herschel. Carol seems to be safer now, she's moving into the slot Andrea should have had if the writer's didn't screw her character up like they did.
I'm in the Carl is a psycho camp by the way, I don't care that much that he killed the teenager, that was justifiable considering he was part of an enemy group that was attacking them and he did not drop his weapon, but that he didn't seem to care that he just took a human life was creepy. He looked him in the eyes, pulled the trigger and then acted like "Had to be done, dinner ready?".
A normal human being should feel at least conflicted about the situation, he should ask himself if his decision was right and even if he was sure that it was right he should be able to empathize with the dead kid. That kid could have been Carl running into three Woodburyans hiding in the woods, would he have dropped his weapon or would he have tried to do something instead of hoping for mercy after being defenseless?