Unfortunately I don't know much about the DA universe presented outside of the games, so I'll take your word on it.
Though now that you mention it, a character who is neutral, or equally cynical of both sides, could be interesting as well. Sort of like the chorus used in Greek plays.
Fixed.
But yeah, Evangeline is a really cool templar. She criticizes the templars as a whole for the use of phylacteries, and calls phylacteries a form of blood magic, but at the same time, she turns around and gives mages a good finger-wagging when they get too big for their britches.
She unfortunately is killed by Lambert.
Cullen....I'm really curious on where he goes as a character from where we left off. He suffered the worst that mages can throw at him, and he's seen the templars grievously abuse their authority over mages and Meredith get way too involved with politics that by Act 3, I couldn't even identify the civil problems as separate from the chantry ones.
Example: Templars now guarding the Viscount's Keep and Meredith acting as defacto Viscount for three years, the templars trying to oust Aveline from the Guard Captaincy so they can consolidate power, Meredith outright stating that she is the only one qualified to declare when she can step down and none other, and she vetoes the city running itself or keeping anyone from stepping forward to try and take Marlowe Dumar's place.
Add in Dumar's codex entry (read it today while repalying DA2) specifically says in the first line that it was the Chantry that put him in power, I don't see why Elthina couldn't get involved and help ease the transition and put someone else's name forward.
Cullen has probably gone through more than any other npc in the games, and it'll be fascinating to see how he develops as a character as a result.
On a side note: I was completely unimpressed by his incompetence as Knight-Captain. I presented evidence to him that Anders was planning something, and had Anders with me at the same time, and nothing is done. I let him know I know of Alrik's tranquil solution and have evidence that it's happening, and he ignores it (so does Elthina.)