I mean I get and agree it would be annoying/bad writing that Hydaelyn was the bad guy all along - but this is a common trope for the franchise. I mean things like FF15 just left a bad taste in my mouth due to it. So can't say it hasn't happened before.

That said I think the angle of tempering is interesting because we're looking at base level idea of tempering. The trailer said these are really old primals. I still think their existence was out of people simply trying to explain the world and the cosmos. We need only look at religion. You can look at how the Bible says God gave mankind free will. Hydaelyn as a primal would do the same. I mean you want something that appeals to and subscribes to your concept of free will. Ascians simply see themselves as a necessity so they get behind their thoughtform primal. It cannot temper us unless we are believed to have actual free will. That even means at the risk of rejecting her.

She is our idea of what a "good god" should be even if she's a primal.