After beating Dragon age inquisition I didnt recall encountering any abominations which I felt odd considering the rip in the fade. I feel like unless I just missed them Bioware didnt put them in because it would be too obvious that freeing the mages wouldnt be in the best interest of everyone. Since lore wise abominations are incredibly powerful and can level an entire village with just one.
Also was there a reason why the templars werent able to just decimate the mages due to the fact that their powers are specifically tailored to fighting mages. Seemed like a mage templar war would have been over pretty quickly.
As others have said they don't really need to, also Most mages are way beyond any demon's attempts to poses them, Kirkwall was a giant focus for dark magic which is why they were so common there,
As to this point, One Senior enchanter is worth an entire company of templars, the reason why the war suddenly went from a stalemate to the mages losing was likely because the losses at the conclave hit them harder, the templars lost some soldiers, the mages lost a good number of their best people who they relied on to make up for most of their people being more or less helpless, also from what i have heard the templars annulled allot of mages who didn't know they were even rebelling yet before they could join in,