Faith, yes. But also mages/templars, how one relates to Corypheus as well (also about faith and magic's place in it). I see it as a final bookend to Anders' view of magic and Asunder.. and who the Inquisitor is in relation and response to that..
The champion of racial relations angle just comes off out of left field.. like a side story, trying to force it's way as the main story.
I think the game is about who the Inquisitor is in relation to Corypheus, yes. I'm not sure what you mean by "magic's place in it" though. My reading of it is that it's about how faith is something that always requires uncertainty....which is something Cory couldn't handle, and Quizzie has to. Cass's storyline does a much better job of laying this out than Quizzie's, but I think that's a side effect of how the theme only works if you play as a strong Andrastrian believer. Quizzie--even if they were only human-- is allowed a full spectrum of beliefs, so this can't be as reinforced as it is with her.
The magical themes in the book are a continuation of DA2 and Asunder, yes, but they aren't and have never been just about mages. Magic affects everyone, and on a deeper level, it's not really about magic. It's about freedom and control and how we treat people when we fear them. In DA:I, it moves away from this, because really the M-T quest isn't asking us who is "right." or "who we should side with" It gives us reasons beyond morality to side with them and then tries to show us that both went too far, and the initial conflict is set aside for a new one. It's asking us "what do we do with a group of people who became so fanatical that they were led astray?"...it's coming back to faith, again. What do we do with faith that's been twisted? Can we have faith in these flawed people? Would it be worth the cost?
And huge parts of the game like Orlais, the Grey Wardens, and the Well of Sorrows didn't really have a huge connection to a mage PC. I think some of this may be your own bias, if you're someone who naturally gravitates towards the mage-centric ideas in the games?
As for the champion of the racial relations....not sure what you mean there. In fandom? Because the game really doesn't support that as a narrative anymore than Origins did. Quizzie doesn't work for dwarves, she works to save everyone. There's a small side effect, seen really only in a few minor NPCS, where it challenges people's assumptions of what dwarves are, but that's tiny and isn't really carried out in any meaningful way. But it's natural for people to be attracted to want to further explore that angle in their posting and headcanons, since it's a present but only partially explored aspect.
...I'm sorry if this conversation is annoying to people here, but I often find it's through disagreements that I sort out my thoughts better. I'll try to post more silly dwarf stuff later, hehe.