I agree it will be addressed for those that did it. But my original point was that the OGB can't have some huge major world shaping impact, if the OGB is a big massive deal then you end up with 2 world states that you can never have a single story run through and be coherent for both states. As I said earlier, by its very nature the OGB impact has to be relatively minor on the world.
The only way around the OGB not existing in a big chunk of the play throughs and still having it be a massive impact on the world states is to have a powerful figure rise and if its a non OGB run then its a new dude with a new backstory, if its a OGB run then its Morrigans bouncing joy. Personally I think thats a little weak in story telling but they really wrote themselves into to sticky mess with a damn god baby.
Whose to say it has to be a new character. The idea of the Dark Ritual is basically making a deal with the devil to save your own life, so whose to say that in the absence of the OGB, you may be forced into making a deal with Flemeth later on. What I'm saying is whose to say Bioware doesn't have major world-shaking plans that revolve around whether the Warden did OR did not perform the Dark Ritual. Whose to say there won't be specific outcomes or repercussions depending on the choice you made and not whether or not you made a specific choice at one time. The writers at Bioware knew generally where they were going and what it could mean and even if they didn't that doesn't mean they can't work with it later on to make that choice meaningful.
In other words, wait and see. Like I said before given the point in the timeline, it's not likely relevant for Inquisition.
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As for the Warden (be they the Hero of Fereldan or Orlesien Warden-Commander), I'm fine with them not showing up. Their story for the most part has already been told and if they chose to bring them back it wouldn't really be the same. You can't copy/paste the characters from Origins, not with the new engine and visuals and then you have the voice thing. Too many complications and for those new to Dragon Age, it won't mean anything. Better to leave the Warden be. Let them do their own thing elsewhere until they eventually drop dead.
I noticed some people took that conversation at the end of DAII as some confirmation that the Warden AND Hawke both disappearing meaning they both have major roles to play later. I did not. What I interpreted it as is that the world is in chaos and two of its most recent living heroes suddenly going AWOL meant they were both otherwise occupied by something that was potentially related to what was happening. Meaning the Seekers couldn't count on their support so they needed new heroes to step up. That interpretation is more inline with what the devs have said about Dragon Age being more a story about a world with many heroes, rather than A hero's story. While there is a story surrounding the Warden's absence that we will be hearing about in some form according to the devs, it is not just the Warden's story, it never was.