I've seen two games do it worse: DA:O. The AD has about 5 minutes of screen time, and Loghain - aside from his cut-away scenes - doesn't appear after Ostagar until the Landsmeet sequence. Bioware really needs to look at how ME1 and ME3 (I shudder as I type this line) featured their villains in their recent productions. JE and BG2 are better examples.
I felt like Loghain had a far more visceral impact in Origins than Corypheus does in Inquisition, and when he actually appeared within the game he was never a pushover. Based upon my experience with Corypheus, my Inquisitor needn't have brought companions, armor or weapons to the final fight. All that the Inquisitor had to do was gently blow in whatever direction the darkspawn-magister happened to be standing, and Cory would basically fall right over??
Look I know that what I just said is an exaggeration, but after the Archdemon, the Architect/the Mother and Knight-Commander Meredith, Corypheus just wasn't much of a threat other than as I said - - - in name only. That was never my impression of his franchise predecessors. So, yes that is a failing for this game.
Cory appears in Dagna's crystal recording, he is seen in memory fragments in the Fade, and later very briefly glimpsed at the elven temple. Other than Haven, that is it ..... I mean seriously, c'mon, what happened here is content changes that scuttled their main bad guy. This is not the Corypheus of Legacy by any stretch of the imagination.