While I agree that the Circle system failed, your other point is debatable. The plot of Jaws of Hakkon is started way back in the backstory by those same Avvar mages creating a monster, as Komandor already pointed out. (And it's so strange to find myself agreeing with him twice in one thread.) The Dalish system fails at least once each in the first two games, and while I don't know them to have yet failed in Inquisition I don't think they're done making new content for it yet. So, the day's still young there. We don't actually know what's going on in Rivain but they do the same thing Anders did, which I think is the same thing those Avvar did; unless they're much better at it than both the other two practitioners, the same thing is going to happen. And even Dorian, who is the best thing in the games to come out of Tevinter, is to some degree ashamed of the place. If the White Circle system as it was practiced before Asunder failed, it's far from the only system for dealing with magic that bad things resulted from. And the really serious bad thing that comes to mind when I think "failed Circle" was at least contained in a Tower on an island which as far as I know has no usable bridges to it.
He didn't argue that nonmages can't be dangerous or that mages can't do good. He's arguing that the reason Hakkon is a danger is because there were free mages.
I suppose that depends on what you define as success and failure. When I point out the various societies as examples of success I score this by a Mage's ability to live side by side with their people while maintaining control of themselves and their abilities. All the societies I have mentioned have displayed this. Now if your standards for working Mage freedom are that Mages are 100% complete saints, absolutely no bad apples and never ever make mistakes or questionable decisions then Mage Freedom will of course always be a failure.
The Jaws of Hakkon are ONE Avvar Clan, composed of Warriors, Rouges and Mages WORKING TOGETHER. They ALL made questionable decisions, not just the Mages. The vast majority of Avvar had nothing to do with their plan, the majority of Avvar Mages had nothing to do with their plan. If you deem that Mage Freedom doesn't work because a few individuals make poor decisions then by that vain all of civilized society has failed. That is an unreasonable standard.
The Dalish cases you cite, presumably Merrill and Zathrien, are both cases of poor judgement. Merrill and Zathrien did not make poor decisions just because they were Mages but because, like everyone, they are fallible and flawed. You will note that both of them while dealing even with Demons and Blood Magic maintained full control and did not spontaneously erupt into Abominations nor did they control or lead anyone by force.
If every Dalish Mage acted in with the same accord then the Dalish would cease to be, but as you know they have gone on like this for hundreds of years and their Hunters, who vastly outnumber the Keepers, are content to let them lead. The Dalish had Free Mages long before they became nomadic and is was not their Mages that destroyed them, it was the Chantry. Logain, notably non-Magical, made poor decisions as well and did more damage than Merrill and Zathrien combined.
You mean by being the first group known to create a possessed-dragon-abomination that had the power to wipe out the only country holding back the second blight with the aim of unleashing it on said country? How exactly does that fall under the "greater good of their community" or anyone's notion of greater good for that matter?
Truly, a ringing endorsement of mage freedom if ever I saw one. Maybe you would care to review your "FACTS"?
The Jaws of Hakkon were one Avvar clan composed of mostly mundane men and women. Mages were a small yet crucial part of their forces. Do you really think that had the Jaws of Hakkon not had Mages they would have all just given up and gone home? You forget the fact that they were stopped by a Free Mage, Inquisitor Ameridan. You also forget that Mages are crucial in the fight against Darkspawn and without them Grey Wardens would not exist.
Another fact that people like to forget/ignore: Every civilization with free mages is also more or less run by them. They nearly all have a small mage upper class and a big "normal" people lower class.
There will never be equality, because mages and "normal" people aren't equals.
Your statement is completely incorrect. Tevinter Mages rule. Dalish Keepers lead out of tradition and not by force. The Avvar are led by Thanes and their Auger only advises while other Mages are as equals among the warriors. Warden Mages are treated equally and can be of any rank in the Order. The Rivaini Seers are only Spiritual leaders and meet once a year to pledge fealty to Rivain's Queen/King.