I would like to see the context in which the "developers" said Cullen was a moderate character, because it's hard for me to see it with the larger majority of his presence in the games. At which point is he moderate, in their view? Do they mean he became a moderate character at the end of DA2? I can see that being the case, and that we'll see evidence of it in his next appearance. If they're saying he was a moderate character throughout DA2, I can't agree. He certainly wasn't a moderate character at the end of DA:O.
WoG, Cullen is a moderate Templar.
“I like Cullen. […] And there are things I think can be done with Cullen. I like the idea that he has confronted probably the worst that the mages have, he’s encountered the worst of what mages can do. Yet he hasn’t done what some Templars have done, like Meredith, or—I keep wanting to call him Knight Divine—Lord Seeker Lambert in the novel, how they have reacted is to become very anti-mage and very judgmental and to paint all the mages in the same basic plot, a few bad apples spoils the bunch. Cullen to me represents another side of Templars which is a side that we need to keep active. Not all Templars are these heartless bastards who would happily torture mages, that’s not true, there are Templars who are good people. I think Cullen is a good man who recognizes that there are dangerous in magic, dangers that have to be dealt with, but he doesn’t lack for compassion and doesn’t try to say, “Well, let’s take the hard approach and kill everybody and let the Maker sort them out.” —David Gaider
As far as moderate for a Templar... well... I think the scale goes:
Thrask>Grigoire>Evangeline>Cullen>crazies>Lambert>Meredith>abusive aholes who are abusive because they're just sadistic pricks
When the extreme right end of the scale is full of all the Lamberts, Merediths, and Mettin's and the like, it leaves a LOT of room in the middle. =p There just aren't many on the far Left in the Templar Order.
As Evangeline puts it, those that feel the way that she (and Cullen) do are often held up as an example. The difference between her and Cullen is that he tried to maintain his position to keep himself in a position to do good when he could. While that wouldn't be enough for hard liner mage right people, it doesn't change the fact that he IS a voice of reason in the Order.