I dunno if anyone's touched on this, but in a recent interview they were talking about zutara, and the way I read it made it seem like they hinted it wasn't going to happen. of course this is just my opinion, because they didn't come out and say it. But they said:
DIMARTINO: And I never would have thought that the potential Katara/Zuko romance was going to be so ... you know, so big for people? Because honestly, that wasn't our intention from the start (laughs).
KONIETZKO: We knew about it...
DIMARTINO: We knew there would be some tension, but it wasn't like we were going to play that up too much, so it's cool to see people getting into that romance stuff.
I dunno, maybe it's just me. I'm not much a of a shipper, I'm neutal, so I don't care. All I want is the truth! It sounds like they weren't planning to have much zutara, and are still not planning to. lulz.