Your ideal Divine

If there's a demon strong enough to kill the First Enchanter involved in the Harrowing, someone is doing something very wrong to begin with. And if there's a morale blow... so what? You can get back up and fix things.

True. But since I don't think we've once ever seen someone get possessed by a demon during ordinary sleep, I'm fairly sure it's virtually nonexistent.

To put it another way, we've never seen demonic possession that did not either come from outright inviting a demon in, or through a botched demon summoning.

Leliana. No one should be imprisoned just because people are afraid of something they cannot understand. I think mages deserve a chance and Leliana can give them that. We'll see whether that works or not.

I think the fear is based on the fact that they do somewhat understand it. Or at least they understand the bits they need to.

I never take Vivienne at her word. Ines is inferred to be a Senior Enchanter (which is why Wynne wanted her to be present at Cumberland) who was researching a plant that was rumored to grow in Blighted soil after Ferelden suffered Blighted lands after the Fifth Blight, and she presumably had permission to be out there. Wynne is a Senior Enchanter, and she asks permission to leave the Circle to help the Warden during the Fifth Blight. Asunder also mocks this by pointing out that she has certain liberties that other Circle mages do not have.

Funny enough, when Wynne is trying to persuade you to re-join the Circle (if your Warden is a Circle mage), you can tell her that the Circle of Ferelden is "an oppressive place", and she says you can try and change that as a leader of the Circle; she even says that this is her dream. Supporting Leliana as Divine is probably something Wynne would have approved since she says in the City of Amaranthine that her opposition to the Circles breaking free is that the Chantry would kill all the mages rather than see them free.

About Quentin: You said, never existed in the real world a serial killer with crazy reasons and their own tools? No one was necromancer between them. Anyone who has committed a lot of killing, until the police was able to realize who did it? And they were no mages, ofc. Meredith stopped the investigation, she declareed to wasted time, and wrote an apology letter to Gascard du Puis...

Considering every mage a potential murderer/criminal is stupid. Also, the idea about mages bringing the world to an end. Tevinter was an empire for more than a thousand years before the First Blight, and it`s still an empire full of people, not abominations by the time of Dragon Age. Ruled by mages all the time, and still not overrun by demons.
As for non-mage criminals: what about some "nice" characters like "Mad Emperor" Reville who invaded Ferelden and his successor Florian who allowed some "entertaining" things to be done in conquered Ferelden. Not to mention the way chevaliers and nobles in Orlay - the most holy empire - are behaving. Or just to think about other "innocent" leaders like Loghain or Meredith. The problem is not being a mage - a bloodthirsty/murderous king or emperor can be much worse - but what kind of human being you are. Indoctrinating mages about magic being a sin (what the Chantry does constantly) can only lead to unstable personalities, and potential troubles/insanity. The Chantry was actively inhibiting any kind of research about how to defend against demonic possession - they like the status quo, which is complete control of the mages, including their abilities. Useful in case of Exalted Marches, for instance.

Like Cullen said in DA2, Act 3: "We have a god-given right over mages". Or something like that. My Hawke never forgave him for this statement...

I've actually already had to answer most of this.

I've already conceded that the mages are innocents who are being locked up, so claiming that I consider every mage a "potential murderer/criminal" isn't helpful. Likewise I'm not arguing that most mages are capable of bringing the world to an end, so that argument doesn't help either.

And the bit about non-mages being dangerous too... I've lost track of how many times I've answered that one. Yes, non-mages can be dangerous, but you don't help anything by pretending that being a mage doesn't automatically make someone a heaping load more dangerous than they would otherwise be. A Tevinter Magister is basically an Orlesian noble with the additional problem of having a form of magic that gets stronger the more inhumanly they act. Quentin is basically a normal serial killer with the unfortunate complications of being pretty much impossible for his victims to fight off and being capable of setting demons on the people who want to stop him. And if I don't see that as enough to justify the Circles without the possibility of mages unwillingly becoming abominations thrown in, I'm still alarmed that pro-mages don't even seem to be thinking about it.

And the "indoctrinating mages about magic being a sin" thing is something we don't know they're still doing after DA:I (to the extent that they were, and even Catilina concedes they weren't all doing it) that I never approved of in the first place. And the inhibiting research thing is another thing I don't approve of, which we know Cassandra at least seems inclined to stop doing since she expressed an interest in following up on Pharamond's findings. (In the same vein as my last aside, Pharamond was given his orders by the Divine.)

Your argument is a bit similar to a fundamentalist one. It`s like imprisoning every gifted child, because s(he) may discover a new terrible weapon. Or every IT expert, because s(he) might bring the Internet down.
I`m not arguing about Tevinter Magisters. There is no Tevinter Magister in an Orlesian Circle, I am sure. A new Divine has no authority over Tevinter. In Dragon Age world, magic is a powerful skill, which can cause both good or evil.
You are judging mages based on the potential harm they`re capable. Based on this, every gifted member of a society in DA should be allowed freedom only based on their potential of destruction. Meaning, only harmless idiots should be completely free. A good warrior is a danger, a learned scholar is a threat, a noble / king / emperor is a menace and a mage a living disaster. All this sounds crazy, but it`s just a generalized extension of your viewpoint. Why restrict the "danger" criteria only to mages, and not apply it to everyone?
More than that, what about threats like an Archdemon, Corypheus, Solas? Especially Solas. How do you propose to fight Solas, for instance, without any kind of magical knowledge?

The problem here is control vs responsibility. The Chantry have chosen control. Meaning, controlling the mages by imprisoning them, restricting what they will learn and how they`ll do it. Instead of developing responsibility and understanding about magic in case of every mage. Of course, insane/irresponsible mages are something else and must be punished, but it`s the same with insane/irresponsible warriors also. Or king, or tyrants.
It seems to me that in DA universe magic / the Fade is rather the norm than the exception. Maybe Thedas has became mostly non-magical because of the Veil. I don`t know. BW is quite inconsistent concerning DA lore. But if magic is the norm (or was at least) it`s a vital knowledge for survival, and not something to be repressed.

I thought we had, its just that without details we have littler confirmation in how the College of Enchanters are (presumably) handling 'mage problems' despite how the epilogue claims they are "finding new solutions to age old problems". Its like trying to find out how a Divine Cassandra presumably reduces abuse/corruption within the Circle, even though we have literally idea how she is doing this.

It's not that we think it doesn't happen, but we are not sure in how they are handling it--let alone if they are successful at it. That being said, there is a small subset that honestly believes that the lack of fear in being brought to a Circle/living in the Circle reduces the general abomination rate. But its not like we can confirm this one way or the other.

Can't? Thrask's daughter, Evelina, Meredith's sister, that miserable mage at the final battle, Huon (lost his mind in Circle), Orsino... The distress/fear/despair don't have any effect?