Thank you for your responses. I might be a little less wary of him now. He does not seem to be in his Templar armor in the Last Supper screenshot. Is that significant?
Personally, I think it is significant. As someone else pointed out, the inquisitor says in the trailer, "Whatever we were before, we are now the inquisition." And if Cullen is going to be a military adviser of some sort, that means he is going to be advising the head of the inquisition ... not the head of the templars.
IF he is still a templar, then what I'm picturing is him and a few other loyal templars have left the Order (under Lambert) and are now serving the Divine, along with Cass and Leliana. Being a templar is a very sacred and personal thing for Cullen, so I don't see him giving that "sacred duty" (as he sees it) up lightly. Someone would have to make it so impossible, so reprehensible for him to continue being a part of the Order for him to leave it. As repulsed as he was by Meredith actions, I don't think they were enough for him to ditch the Order. So, I'm foreseeing a variety of possibilities here...
1. He was removed from the Order against his wishes. This would interesting story-wise and I think it would be cool if we had to rescue him from a prison or something (for betraying his knight-commander or perhaps for not siding with Lambert). Alternatively, they could've told him (for example) join with Lambert or leave the Order, and he chose to leave, but somehow I don't see him doing that. The Order (or rather, what the Order stands for) is too dear to him. Then again, he's been through hell. Who knows what's going through his mind at this point.
2. He broke away from the Order and has formed/joined a sort of rebel Order loyal to the Divine. To me this seems the most likely case. He was, after all, wearing the templar uniform in the survey leak, but, then again, things change. He was dressed in non-templar clothes in the War Room concept art.
Both of these possibilities will allow his character to continue to grow, and I really can't wait to see what's become of him! The reason I love Cullen is because he's such a well-written character. He is written with such complexity and nuance; he is not a black-and-white character, so to speak. He is a good person who has done bad things and wrestles with what he's done and what he perhaps should have or shouldn't have done. He is, in effect, very much a real person, flaws and all. For an NPC, he really shines in DA2 (which is when I first met him).
He is handsome, and that's definitely a plus when it comes to wanting to romance him with my character. Is he personally my type, no not at all. But I like my characters' boyfriends and girlfriends to be good-looking people; if that's shallow of me, oh well. Hence why I'm so disappointed with the current crop of potential companions, but as always, we'll have to wait and see. Maybe I'll come around to one or two of them.