Star Norman Reedus previews what's ahead for various characters in season four:

“I think [the governor's] evolution of a bad guy is not dead yet. To reach the comic book status, like in the comic book, the guy is so ferocious, he’s on the precipice of becoming that guy. So the last episode wasn’t about the war, it was about who is becoming what in that world. Carl, what he has become, Rick what he has become, what Daryl has become. That’s the intro into season 4... [Carl's] dark right now. I think he’s going to get much darker. I think all of us are real dark right now... I think having these people relying on [Daryl] is something he’s never had before and he has this new sense of self worth that he never thought he could ever have. So through these people, that’s the glue that’s keeping him around. I think he’ll go hard again after [killing] Merle. I think Merle is going to shut him down for a minute.”

[Hollywood Life]

Executive producer Gale Anne Hurd discusses why the main characters haven't seized control of Woodbury heading into the fourth season:

Who knows? The Governor is still out there with Shumpert and Martinez. They’ve still got significant firepower. If they go to Woodbury, at this point, Woodbury’s not as protected as it used to be. I think everyone was traumatized by what happened, and I think they feel safer in the prison. Is the whole population now in the prison, or are there still people left in Woodbury? I couldn’t tell you that, to be honest. I think that’s a decision we’ll come to find out in the new season.

She also discusses whether the zombies themselves will be more heavily featured next season:

Yeah, I don’t think that in a show that goes from season to season — we are living in a zombie apocalypse, we’re living in an apocalypse where we know that unless someone has brain trauma, they’re going to come back. Regardless of how they die, they’re going to turn into a zombie. So I think it would be a good bet to say that the zombies become more threatening in seasons to come.

There's more at the link. [IGN]

The actor who plays Milton talks about shooting the final episode of season 3:

http://insidetv.ew.com/2013/04/01/the-walking-dead-dallas-roberts-milton-andrea/

Think the Governor is gone for good after he slaughtered his own citizens and took off with Martinez and that other henchman? Think again! “The Governor is still out there,” says co-executive producer Denise Huth. “The war is not over. Rick and our group here won the first round and scared him off.”

What about possibly budding psychopath Carl Grimes, who shot another young soldier who appeared to be handing over —albeit waaaaay too slowly — his weapon? Where is that character going when the show picks back up? “Carl’s changing,” says Huth.

It’s a huge wake-up call for Rick. And it’s a big fear for him moving into the next season. Is Carl going to be Rick, or is Carl going to be the Governor? And right now Carl could go either way.”

Also look for the world of The Walking Dead to expand well beyond the prison-Woodbury feud.  “We will be getting into more world building, more civilization being brought back,” says Walking Dead creator Robert Kirkman. “A little bit more of a bigger sense of community.” And don’t assume it’s gong to be smooth sailing with all those former Woodburyites now moving into the prison. “What’s going to happen as these two groups who literally were at war with each other moments before, how are they going to integrate?” asks executive producer Gale Anne Hurd.

Source: http://insidetv.ew.com/2013/04/01/the-walking-dead-exclusive-season-4-preview-video/

Walking Dead season 3 finale had 12.4 million viewers, a record!

http://insidetv.ew.com/2013/04/01/walking-dead-finale-ratings-3/

Coincidentally, Game of Thrones season 3 premiere was same night and ALSO set a record!