DreGregoire wrote...
I don't think that there is enough information/interaction on/with Cullen for anybody to say without a doubt what goes on in Cullen's mind and he certainly does not show any evidence of being damaged.
Were we told that we wouldn't have access to Kirkwall in DA3? Cullen could be there still or he could have been transfered elsewhere. Conversations in DAO and DA2 did give me the impression that there is a sharing of talent between Circle's, not only in regards to mages but templars as well. Also I was pretty sure that it is rumored that at least Cullen's voice actor will be voice acting for DA3, just a rumor though. 
His screentime has been limited, but I think we've gotten some good hints that he's damaged. There are a couple of dialogue options in DA2 that suggest Cullen is suffering from PTSD. I've been told by others are who more knowledgable than I that some of his behavior is textbook. Whether that's true or not, I think his traumatic past sets him up for an interesting future character arc to continue his evolution, if we see him again.
He also seems to have done some healing since DA:O, and then he gets the rug pulled out from under him again at the end of DA2. He's now experienced two Circles where he's seen the whole spectrum of treatment of and by mages. He's had to decide for himself what he thinks the Order stands for, and as a result, defied his superior officer. So, what does he do now? If there are no Circles anymore, and the "official" Templar Order no longer serves the Divine... what's a dutiful templar to do? He could be an interesting window into that conflict, particularly given his personal growth issues.
Going back to OP's point, if Cullen is a LI, I think it would be fascinating to see how he would deal with a mage PC. I think he'll inevitably have issues with trust, since even in DA2 Act 1 he thinks that templars cannot be friends with mages. But, he's grown a lot, particularly by Act 3, and falling for a mage could even be part of his healing process (LOL or make him regress!). Could be interesting stuff, for those inclined to explore it.
And, will we see him again... ? Greg Ellis is a bit more than just a rumor, since the actor himself tweeted a pic of himself recording "Cullen" lines before he deleted it. But we won't know for some time what happened, whether he was wrong or just an NPC or a trailer VO or... maybe Awakenings!Anders, risen from the grave! So maybe a strongly suggestive rumor??
If he's not in... yeah, disappointed, but I'm looking forward to the game regardless. I don't think anyone need worry about the Cullen thread storming BW headquarters... but we can't speak for all Cullen fans. They come in all shapes and sizes.