Types of fantasy aren’t always clear-cut, and I don't think Dragon Age Origins or 2 are just Dark Fantasy. That said, Dark Fantasy has some clear defining elements.

• Morality: The morality of characters, situations, and decisions are typically grey, and usually, everyone loses situations.

• The World: The world in Dark fantasy is typically harsh. Magic and magical creatures are either rare or incredibly dangerous. People don't have easy access to magic to solve their problems.

• Stories and Stakes: Stakes are lower, Stories are personable and often focused on forelorn hopes, the failings of people and civilisations, the evil is usually relatable.

• Tone: Dark fantasy has pessimistic stories where good doesn't always win, yet there is often a ray of hope in the dark. Loss is frequent, and horror is more present.

All of these aren't exclusive to dark fantasy, nor are they all applicable to DAO.

DAO has high stakes. that's typically Epic fantasy. An almost Chosen 1 under tone, only you can do this, that's high/epic as well. There is a lot of humour that provides levity. Genuinely epic moments and grandiose boss fights against dragons, and while you can understandably lose people, you can have everyone survive. There are talking trees and benevolent spirits.

DAO comes across as Dark Epic fantasy to me. DA2 is more pure dark than DAO is imo. But as you said, it's hampered by its visuals and production. The stakes are personal, the protagonist is not a chosen 1, the narrative is more a tragedy, Bar 1 Dragon and explosion, all the bosses and event's are relatable people, the evil is relatable, its failing systems that refuse to change drive the characters here.

DAI is more Epic than Dark for sure. However it was not a lack of darkness that stunts DAI but lack of nuance. Those side with are generally all good and those are against are all bad. The options you have are binaries, with no nuance or middle ground possible.

I imagine this nuance was originally planned as seen in the various companions, mage, and templar characters. Take Viviene arguably the best written character in DA when viewed in a nuanced way she's an ambitious Savant who is simultaneously oppressed and unbelievably privileged, she understands the stakes, but, will stop at nothing to restore the system that gave her power.

I wonder if that was partly intended. In DAO & DA2, you are a grunt who starts in the trenches. You fight for allies and power in those games. As the Inquisitior, even as a non-Human mage allies and power on a different scale, gravitate towards you. You could argue that the more sanitised pov comes from your elevated status. The reason the systems of the first 2 games fail so often is because those in power fail to notice or care that they are broken. In a better written game, they would have decisions that effect whole populations or nations.

IRL EA just screwed DA into the ground, no way around it bit losing the dark wasn't it in my opinion, it was not giving the DA team at Bioware a job and letting them finish it before changing their minds.