Didn't say he wouldn't be in rough shape, in fact i wouldn't be surprised if he was but a year or two from his own calling assuming he hadn't gone already but I'd also point out he isn't the same as most people of that age.
He kept fit and in shape despite his advancing age, he was a capable warrior who fought toe toe with a Warden less then half his age.
Just saying.
If Bioware casts him, i wouldn't oppose it, in fact I'd love to see Loghain again.
I feel like his story is over. There's nothing more to really explore, imho.
It's very likely that the Dark Ritual didn't take place and he died a heroic death, I believe that was an option in DA2 as well.
I'm just saying, he'd probably be decrepit and I mean, his redemption is over if he's lived. What else is there to tell?
I enjoyed him but it'd be like seeing Anders again for me, what more is there to know?