The Walking Dead - Episode 2.11 - Judge, Jury, Executioner - Robert Kirkman Interview

You killed Dale! Are you disappointed that you weren't able to explore the romance between Dale and Andrea that was such a big part of the comic series?
Robert Kirkman: Not necessarily. I have talked many times how much I like the difference between the comics and the show. There are going to be big plot lines that we may not necessarily get to, like the romance between Dale and Andrea. If you think you really want to read that story line, that's available in the comics, and I highly recommend you pick those up. The show is always going to be a different animal and the decision to kill Dale off was a big one and it wasn't one that was made lightly.
Dale has become the moral center of the group and especially in this episode for him to be going around and saying, "Let's retain our humanity," he's the last guy that's preaching that at this point with Rick making the decisions he has been making of late. To lose this guy at this moment means so much for this group. It's going to be such a monumental death that it's going to affect things a great deal moving forward. It seemed like the right time and that to me, all the stories that are going to come out of this that people haven't seen yet, are worth losing the Dale/Andrea relationship.

How will not having Dale's voice of reason affect them? Could Andrea potentially fill that role having stepped up late in the game to vote to spare Randall's life?
Kirkman: Losing that role is very important. This is the time more than ever when they really need someone to stand there and say, "Hey, this is not the popular decision, but I'm still voicing this because it needs to be said." They don't have that. Now, we don't know how they're going to deal with Randall and we don't know what they're going to do as Rick and Shane continue to butt heads. They've lost a very important piece of their ensemble, and so they're not going to be able to make the same decisions they would have made and that's really going to affect the group as a whole. They are kind of in a bad place and we're going to have to deal with that.

Source: Full interview @ The Hollywood Reporter