Yeah, and I guess a teaser trailer isn't really indicative of the tone of the actual movie. It just felt more like Interstellar (As others have said) instead of a movie based on the fantastic four comics. Although I haven't read the ultimate ones so maybe its fine the way it is if its going for that. Either way its a pretty good trailer for what it is and I'm actually interested in the movie now.
Maybe it's different for fans of the comics. I don't read the comics and have only seen the first movie. While it's definitely darker looking, and apparently the origins are different, I still relate it as Fantastic 4, as the basic premise is still there. If a random movie came out with a dude made of rock and another of fire, everyone would call it a Fantastic 4 rip off lol
The problem is that this angle is a horrible fit, and we still haven't had a good movie from the angle that made everyone fans of Fantastic Four in the first place.
It may be a horrible fit if you shove the comic into it, but as a movie about 4 superheroes, you can't possibly know if it's a horrible fit or not. That's why it's an adaptation.