Yeah, I agree that the head morphs are pretty off. Loghain looks too young, Eamon does look too old, Isolde actually looks too young to me (you figure that she's about 30), as does Anora (who is also supposed to be about 30). Alistair def. looks closer to 30 than 20. It's kind of strange...

I think that either theory works well with Alistair spending half his life in the chantry without becoming a templar. I mean, getting the son of the king addicted to lyrium seems kind of stupid. No matter who the Mom is.

http://social.bioware.com/forum/1/topic/9/index/1054532

Confirmation of the rough timeline, anyway.