Indeed. Nothing would have put circles "back into their restive state" following Wynne's "broadcast". Arresting all the First enchanters was a completely idiotic move because it would all but guarantee that every single circle would rise up. Lambert could probably annull one of them, but all of them at the same time? Not a chance. Similarily, not calling the conclave after that broadcast would only have undermined the Divine's authority in the circle, quite possibly led to rebellion as well. Not pursuing the research in the first place would not have changed anything.
Really... the mage rebellion has been an unstoppable avalance that started well over a hundred years ago. Justinia didn't start it. Lambert didn't start it. Adrian and Fiona didn't start it. Wynne didn't start it. Not even Anders started it (he just made people notice it was coming). When the story begins in DAO, it was more or less inevitable we'd reach this point.
I disagree that it is unavoidable, except for with the writing of bioware for DA2. And where do you get the more then 100 years ago?
This was a process that had reasons for occurring:
1) The issues at kirkwall-Meredith, Anders, Bloodmages, abusive templars,etc. You remedy a few of these issues and DA2 doesn't occur and Asunder doesn't occur.
2) Hardliner templars getting in positions of leadership
3) Justinia's predecessor being an old emfeebled woman who was afraid of her own shadow
4) The Seekers being asleep at the wheel regarding kirkwall and templar abuses
5) Lambert being the one to take over at the White Spire.
6) Adrian's plots and machinations
7) Fiona's thumbing her nose at all logic about the state of events and demanding the vote when she did
8) Radical elements gaining power in the mage fraternaties
Look, you can agree or disagree with what the above individuals did and the events that occurred, but I refuse to believe that the mage war was inevitable.
Heck, even in Asunder, if certain people had chosen to play ball, the mages would have had their conclave about tranquility. Would have come to a conclusion, and reforms would have started while tempers and issues calmed down. But no, that couldn't be allowed to happen.
Even if the hard line templars had refused to go along with it, as we have seen in ME preview, Celene would have had no issue using Orlesian forces to back Justinia against rogue templars refusing to follow orders of the Divine. And guess what, there are a lot more Chevaliers and soldiers then there are Templars.