I have only read The Stolen Throne, The Calling, Asunder and The Masked Empire. Of those novels, the only one I think I would recommend consistently is The Masked Empire. It's a solid piece of writing. The mage/templar conflict is present but totally in the background. It focuses on the political turmoil in Orlais. I would guess Gaider's writing style is better suited to the comics. I plan on reading those next week and can report back if you'd like.
yeah, reading G/aider's novel writing it's kinda easy to tell that what he's most used to is game-style writing, like... "if/then"/flow chart kind of dialogue options and stuff -- he's not so much a prose writer. & I have so many problems with the guy in terms of...well, pretty much everything tbh (lmao), but I read TST & Asunder (& I'll eventually get to The Calling) for the sake of getting supplementary lore/info that's hinted at but not fully covered in the games. The frustrating thing about Asunder is that it showed how Varric's DA2 endgame narration was oversimplified -- Anders' actions didn't lead directly to the Circles rising up, there was a lot of shit that happened btwn DA2's endgame and the official start of the war. But then like... in DA:I and out-of-game, in spite of what we're shown in Asunder, Anders still is often given all the blame/credit (depending on how you look at it) for starting the war, & the contributions of other characters (Fiona, Wynne, Rhys, Adrian, etc) get overshadowed. It's super frustrating.