For whatever reason this post ate my ME3 related stuff. It wasn't long but I suppose I'll be even briefer in addressing your point. ME3, in my view, isn't ambitious because it's so nonsensical and inconsistent in tone from start to finish that anything it does right is, in my view, an absolute fluke. More than that, though, if you play a 100% paragon throughout the story isn't really dark at all. And then thematically.. ugh. Suffice it to say I think ME3 is a failure on every possible level besides its character arcs for Tuchanka and Rannoch, and the latter is a total tone shift from the other two games.
Since this isn't a discussion on ME3, I'll not go in to depth on it here, although I might refer your stance on it at a couple of points in reference to your other answers. I guess I'll just write that I utterly disagree with you concerning ME3 and while I have played pretty strong paragon runthroughs, it is still insanly dark as you seem to completely ignore the constant of loss in the game and how each of those victories require sacrifice. Besides, from your arguments, it almost seems that you are claiming that the only way a game is ambitious is if it succeeds, but those are two different things?
There's no way to take the other three games you list as a heroes journey. In Oblivion, you are very much the side character. I mean, I suppose the fact you're awesome at murder and kill everything in your path is "like" being the chosen one, except for the fact that's not really particularly pushed at in the story (as much as there is a story). New Vegas goes even further than this, where there's no heroes journey to speak of in the game at all. In fact, I think it's fundamentally mscharacterizing the brilliance of the narrative to reduce it to that. It would be like saying NWN2:MOTB is a traditional heroes journey. And if that's your view of it, then we just fundamentally disagree.
Now, I don't disagree that what DA:I does is conventional by trash fantasy standards. But fantasy - at least big ticket high concept stuff in the public consciousnes - has experienced a pretty big tone-shift with ASOIAF. By comparison to that series, stuff that adheres to the ol' D&D or Dragonlance type stuff (i.e., most of fantasy, which is, again, trash) is treated as being very bad.
Fundamentally going back on the direction the company has been going since - at least - ME2, if not DA:O, is a pretty ambitious move. It's as ambitious as DA2 attempting a radical move away from the traditional Bioware story. Which I still maintain is a mistake - Bioware just doesn't have the design knowledge to build a game that would work on the level of what DA2 should be and they certainly don't have the writing attitude that would make that kind of game work.
Now somewhat amusingly, I don't consider FO:NV to have a brilliant narrative at all, I actually found it to be really dull and predictable in most cases. Hero wakes up, no reference they are, drifts through wasteland, is just really special, solves all problems by mostly killing everything, becomes the central operative competed by three different factions, and so on. And no, I don't consider NWN2:MOTB to be a traditional hero's journey and consider it quite brilliant, hence my not listing it or even mentioning it, but I also don't see why you feel it is simlar to FO:NV. NWN2 itself, though, is again as traditional as it gets.
After that we get to the central argument that I don't get. If we agree that DAI narrative is the same basic narrative than in most trashy fantasy books, I don't see how we can in any way argue it to be ambitious. The thing is I don't think the classic fantasy stories are considered bad, I would rather say they are considered bland and boring for the most part. The reason I feel we saw the movement away from it is not because they are looked down on, but that there is a want from the writers to do something more, especially more they write.
I assume at the heart of the disagreement here is that when speaking of narrative ambition, can we separate the narrative from the medium. For example, can we say a movie that used this narrative would not be ambitious while a RPG doing it really ambitious. To me we can't, as it is as traditional fantasy story as can be and while one can argue that there haven't been that many stories like it lately, which I still disagree with, it doesn't change the fact that it is as basic as it gets. At least if the argument of ambition was based on what Bioware itself discussed how the game was about faith and hope. In that case I would agree that as a concept it is ambitious, but DAI's unwillingness to truly thematicall engage on those subjects prevents me from considering it ambitious.
As for Bioware having the design and writing knowledge, I disagree on that, but then again I liked DA2 and ME3 and considered them ambitious. However, unless Bioware continues test those waters, to try something new, then they really can't develop better skills at it. If we argue that the only story Bioware should be telling is the basic hero's arc journey, then that will be the only story they can tell and they themselves have in the past seemed to have becomed bored with that narrative.
A reconstruction doesn't have to simultaneously deconstruct the trope. That's why I cited Toppa Toppa Gurren Lagan as illustrative of this type of approach.
As to the merits of DA:I, I don't see why a heavy focus on an antagonist is particularly necessary. Ignoring the fact that DA:I is the only game Bioware's had besides ME3 that actually coherently ties the majority of its main quest to the antagonist, the Elder One is pretty clearly written to be the antithesis of the Inquisitor. I thought that this was so on the nose in the writing that it was one of the biggest weaknesses in the game. As for what DA:I addresses that's both a deconstruction and reconstruction with Corypheus, well, there's a big one. Repeatedly losing as an antagonist actually saps Corypheus's strength. Unlike every fantasy villain since Sauron, he's not a load bearing boss. This concept is stupid and Bioware uses it again and again pre-DAI. The best examples are Sovereign/Saren and the Archdemon.
To have the villain lose in a way that's actually realistic - slowly being whittled down to nothing - is ambitious. And it's led to a great deal of hate specifically because it's not the usual nonsensical encounter where the enemy has an overwhelming force and then just gives up and runs away when the load bearing boss loses.
The Archdemon is really bad example for this, as it doesn't really encounter setbacks that would sap it's strength. Loghain does and that is at least attempted to show weaken him. And yeah, Bioware did attempt not load bearing villains in, wait for it, DA2 and ME3. DA2 doesn't follow that story structure, and yet according to your arguments is not that ambitious, and in ME3 the central point of the game is the Reapers are so overbearing that no matter how many victories you get, it doesn't matter to the enemy.
And again, how is it realistic or ambitious in DAI? We had a ridiculously ineffective villain that was supposed to be this great threat, yet its forces were just unable to do anything against the Inquisition after Haven and his lieutenants basically just talk about how hollowly evil they are. I don't think it has lead to overwhelming hate because of the loadbearing argument, but because the opponent really feels threatening to begin with and is just there to be walked over.
The reason the weak villain is mentioned in the ambition discussion is that Cory never poses any kind of ideological or actual threat, again contributing to the fact that there is basically nothing challenging the main character in DAI. And I cannot comprehend how that can be considered ambiitous in anyway.