I honestly would have wished the Warden (or the Orleasian Warden, if yours did the US) simply became a villain in DA:I. Mind-controlled by Cory to serve as a powerful enforcer on the field and using their connections and influence in Ferelden to help secretly plant anti-inquisition activities and agendas in the country. They would harass your efforts throughout the main plot, showing up to make things difficult and messing with your plans. You'll eventually defeat them as a mini-boss before facing off Cory in the final level, where upon they snap back to their senses and pull some last minute heroic sacrifice to help bring down Cory or the dragon.
Sorta like Kai Leng from ME3, but less **** and for DA:O veterans, a more meaningful rival perhaps.
And yes, it would mean that Bioware would have to give the Warden a voice and a new face. But they have already shown their willing to stop the game in order to give players a chance to customize Hawke, so I see no reason why we couldn't have a third character creator where we also choose one of two VAs (per gender) for the Warden.
But maybe this is all too unrealistic to have hoped for.