First, treating the world as it is presented in the game. Don't move the Mario Bros to New York or make a Final Fantasy film without chocobos or summons.

I disagree with this. Somebody who just wants to see a great movie isn't going to give a damn how close the world is to it's videogame counterpart. You only have two and a half hours to get everything you need to in the movie, and some video game locations are just too weird/abnormal to pull off without spending time on fleshing it out. If you don't spend the time on it, then it will just feel shoe-horned in and pandering. I would much rather they spend the time on building characters and the story, so a location swap might be necessary.

Which brings me to:

Second, the the focus of the movie should not be the plot, which will usually be to get the McGuffin and Save the World. Video games are inherently power fantasies in a lot of respects which is why their plots tend to be paper thin. The drama comes from playing the game, not the beats of the story. For a movie you need to shift that around a bit.

You absolutely need story, and it doesn't have to be McGuffin saving the world. The fans of the game may complain at the change, but we're talking about making a good film and not one that just panders to the fans.

I think these two points are what really holds video game movies back. They are too pandering to the source material to be good. Video games and film are two completely different mediums, and sometimes you just have to change things for the betterment of the film. I'm usually ok with that as long as they capture the "spirit" of what they're changing.

Think of it like converting a book to a movie/show: How it can be done wrong:
Think Deadpool from the Wolverine movie. They kept the look but changed everything that made Deadpool who he was.

How it can be done right: Game of Thrones. They make stuff up and change LOTS of things throughout the series, but they capture the feel and intent of the books VERY well.