I have killed Loghain/spared him/had him make the ultimate sacrifice/leave him as a warden and my warden sacrifices herself. I've tried it all. I think... I understand his reasoning more than I want to. If I'd been so sure an old enemy I hated was trying retake my country, I'd do some shady **** too.

That said, I don't agree with selling the elves, and I had wanted to think he didn't know about it because Howe was a sneaky devious rodent who lied and implied to get Loghain's approval for certain acts. I'm still not sure the tortures were something he was complicit with. I don't recall if they made that clear. They did make it clear he knew about the elves, though and for that and his betrayal of Cailan and the Wardens, I thought making him one was an ironic punishment.

So I wonder how he's fared as a warden and since the Wardens seem to have some big, important business going on, it makes me think it might be possible to see him again. Unless the Devs' canon for him is that he died.
@LolaLei
I agree. Add all that stuff and throw Cullen into the mix and DA3 will be the hottest game of the franchise!

Just imagine ME's knack for inter-character relationship development and the Witcher's sex scene with Cullen!!! *dies*