Yeah, the only time I can see a human/spirit merger not go badly is with a spirit that embodies a "quieter" virtue and a human with a very stable personality. Like Wynne and her faith spirit. She was a believer, not a zealot who could have twisted the spirit -- and the spirit was content with that instead of burning with a motivation to push its own agenda. Though faith could go either way, really, both "quiet" and "driven", I'd still rank it as "lower-risk" than justice, valor or command.
I did not play Awakenings or DA2 so my knowledge is second-hand, but Anders/Justice/Vengeance sounds pretty much like the worst-case scenario for such a merger.
Here's an interesting moment I feel that needs to be mentioned on the topic of spirits that gets brought up in DA2:
Anders ends up having a meltdown that really shook him up. When Merrill responds to him in pity, he flips out a bit and tells her this was the danger she herself willingly involved herself in. Her response:
Merrill: Anders...there's no such thing as a good spirit. There never was. All spirits are dangerous. I understood that. I'm sorry you didn't.
In previous banters, Merrill held up to this idea that it was naturally risky to interact with any spirits, whether they followed 'good' virtues of not. And after seeing what became of Ander and Justice's situation, I admit to agreeing with her on the view. Spirits only ever really know the Fade, and the rifts shows what happens to Spirits who Are forced away from the only world they know. In a sense, they're just as complex as people outside the Fade, but most never seem to think beyond the virtue that interest them. Once out of the Fade, they risk becoming demons because of how easily a 'virtue' can twist around.
As for the case of how much affect Spirit-possessing can have on a person, I think that all comes down on the person as well as the Spirit. Wynne had a good number of years of maturing; even in moments of anger, it does nothing to overpower the fact she has been an experienced mage who understood her strengths, faults, and views in life.
Anders and Justice didn't have that experience; even in Awakening, Anders was portrayed as a carefree, if sometimes cowardly, young mage who wanted freedom yet didn't seem to fully understand what he would do beyond his plan for freedom. Justice (and this is just my interpretation of my Awakening playthrough) was a Spirit who was slowly refining his own views of 'justice' and being human, already developing his own consciousness; in short, he was already becoming a bit more human and losing bit by bit what had made him a 'pure' spirit (which, you could say the Faith Spirit was because it hadn't been effected outside the Fade). Even worse, both Anders and Justice could be seen as immature because of that lack of experience with the outside world. Coupled with Ander's more constant anger toward the mages' situation and Justice's still raw conceptions toward the world, and you get the worse situation possible with Spirit-possession.
It's like having your mind fused with the mind of a friend with some views that contrast your own; it's likely end badly because you both have unique life experiences. it would be mentally difficult because there would be two minds who have different ways of solving problems and seeing the world.
Retour en haut
I won't spoil what happens in the "more human" solution, but the one thing Solas and Varric do agree on is that letting Cole get his revenge would be a very bad idea.
That's very human and believable, actually, so I don't really blame either one of them though I do think they're a bit too focused on only one side of our friend. Both paths work and eventually make him happy and more and better, and I find both joy and sorrow in each solution -- it's just personal preference that sways me towards the spirit side, so I'm hardly free of bias myself.
