I, too, am reticent when it comes down to vidya adaptations, but in this case I genuinely think the Tarnished's story can't be told in any other form than through the video game. I expect them to be aware of this, at least on some level, and to set the movie to run in parallel, or be a vertical slice of a part of the story, maybe even depict the things which happened before the Tarnished got started on their way.

I don't see a coherent way to compress all of that gameplay into a "static" narrative, either... And it's essential to the story itself, it's the primary method through which the story is told, you get to know the characters through fighting them, mostly. And then you have the physical journey itself, it'd be a mess to compress that huge schlep into a two-hour film, it'd come out twitchier than LoTR all in all...

It may work if serialised, but it'd need a good couple of seasons to cover everything...