There is no "corrupt magic" in Tevinter system, such notion was formed by the southern chantry.
Yeah, nothing wrong with human sacrifice. How galling of the Chantry to want to watch these people.
Mate the differences between the 2 mage groups are greatly different. It would be just as asinine as saying that because one group of templars started huffing red lyrium all red templars will start huffing red lyrium.
Your Templar statement is a false-equivalence to what I am saying. A more accurate one would be more like: if you stop controlling Templars with regular blue lyrium, then you will have a problem with some Templars using red lyrium. And I actually would not be compelled to disagree with that assessment. Not saying all of them will go bad, but likely some would, and perhaps enough would to be a problem.
And the problem with non mage organisation is that they will not be able to detect magical corruption. Because they lack the knowledge to do so. The templars for the most part can only fix the symptons and not the cause of the disease.
Even if they cannot preempt corruption, their existence can mitigate the damage done by it, which is worth it for any number of lives it can save.
I was not really even talking about that, though. Who knows how powerful any given Circle can get. If they are creating any kinds of policies, there should be a voice from the other side to ensure the interests of others are protected. Not only that, but also to prevent the kind of in-group/out-group mentality isolation can bring that fuels conflict of any type.
Perhaps the Circle did not do well in getting mages and non-mages to learn to work together, but at least an element of it was there.
And how is magical corruption worse than say... "Let's burn down and alienage, because they might find out I have slept wiht an elf".
Because only a very select few individuals in society can do said burning. The rest of the population does not have that ability.
Anyone with magic can be a blood-mage and/or get themselves possessed and similarly massacre civilians.
The problem with Tevinter is not caused by magic - or even blood magic (though blood magic helps), it is caused by have a slave system, which dehumanized a group of people making them easy to kill and not care if you robs them of basic free will.
Slavery is a symptom of blood-magic, not the other way around. Attempts are made to abolish slavery quite frequently, but they never last.
All the rulers of Thedas can go mustache twirling and kills in hundres - and they do.
YUP, which is why the rulers of Thedas need their power greatly restricted... just like the mages need the same until and unless they prove trustworthy.
I still fail to see how the current magisters of Tevinter are worse than say Orlais.
Because magisters of Tevinter can do everything that Orlesian nobility can, plus blood-magic.
At least Orlesian nobles do not find entertainment in sacrificing children for blood-rituals.