I love Adrian! I'd have gladly taken her into the party as a companion. I actually think her siding with Tevinter would fit better than Fiona doing the same thing - she seems much more hot-tempered and impulsive.
I have some dislike for Evangeline and Wynne, though. Actually, after Asunder I disliked, erm, nearly everyone. Except for Adrian and Seeker Lambert, ironically. But after DAI came, I saw Cole had such fantastic writing, and Leliana has gone through such an interesting journey, and even Fiona seemed alive and sympathetic, so I can definitely enjoy those three.
Evangeline, though... no. Just no. Maybe it's my inner schoolgirl talking, but: if you travel with a guy and his ex, you *don't* make any moves on him. Not classy.
As for other books, I would LOVE to see Felassan again, except that... well... spoilers. Sigh.