Maybe Sophia will be lost for a while so they can substitute a new actress next season and we won't notice? As for Carl, the actor seems on the small side for a 12 year old, so maybe he's not going to grow up to be more than Michael J. Fox sized, and that could cover things adequately.
My wife and I observed that this show has yet to actually introduce clearly BAD people. With the arguable exception of Merle (who's more just an asshole than an actual baddie), everyone we've met so far are not really evil or a villainous type. They're all just survivors, not power-mad, greedy, or subject to a variety of bad-guy stereotypes as most zombie movies have given us. I find this pretty refreshing - pretty much anyone who would be the typical early victims early on in a zombie apocalypse are already dead. There are no cheerleaders, no jocks, no corporate bigwigs, no soldiers. They're all neural chow.
Yeah, I don't think we need any cornball villains on this show.
And that reminds me, did anyone see the History Channels' Zombies: A Living History
? It made the same point - lone-wolf Rambo types won't be as likely to survive a zombie apocalypse than people who are good at forming social bonds and sharing resources - and also delved into zombie lore around the world, real world antecedents to zombie fears (actual history on the History Channel!!!), current events, groups like Zombie Squad that are actually doing some good spreading knowledge of disaster survival tactics, and offered some interesting tips on fighting zombies (leave the samurai sword at home, pick up a tire iron instead). And the ubiquitous Max Brooks got a lot of screen time.
No mention of crossbows as a great zombie fighting weapon, though. Well other than that, it was very well done.