I saw the first webisode series, involving the bicycle/park zombie from episode one. The clips were short, but poignant. Interestingly, the director of that went on to be more prominently involved in Seasons 2 and 3.
He was being portrayed that way, midway through Season 2, but he simply hasn't been written or portrayed that way in the last few episodes. He's not operating as a detached machine. He still expresses strong attachment, and in broader ways than Rick. He didn't know Morgan, for example, but apologized to him on his own initiative, beacuse he felt bad about shooting him. He also risked his life over something broadly sentimental (a picture) of his family, for a little sister he barely knows but who he is attached to. He also interacted with Michonne as a person, not as some kind of guardian getting in his way. Very different from children who have had the attachments/feelings burned out of them... and Carl has already been through probably the biggest traumas he'll experience for the first time. If Rick gets killed, for example, yes, he'll lose his dad; but he's already lost his mom in a far worse way, and had to be the one to cap her. He might have lost his innocence, but Carl is still showing sensitivity and nuance in social interactions, on an almost adult level.Originally Posted by EffEmDoubleYou
The actor playing Carl is also playing things more warmly, not coldly.
So the progression into "ruthlessness" seems momentarily halted. If the writers want to go in that direction, they need to set up his character differently, and the director needs to direct the actor better to not be so warm.