The original Fantastic Four (from 2005?) feels jarring now mostly because of Chris Evans being cast as Johnny Storm, kind of the anti-Captain America. It's like totally against the hero persona we've grown to love over the last decade. (And also the build, he's put on a LOT more heft as Caps.)
It's interesting how it predates Iron Man, the opening salvo (or one of them) by the MCU, now that we see what Marvel built over the years. Fantastic Four is not built from that cloth. It is essentially a film evoking a lot of feelings from the actual comic. I would call it a B film except that it's a bit better than that, but also it doesn't try to achieve as much. If you read the comic and enjoyed it and don't expect more from a film, it is pretty WYSIWYG. The origin story. The interactions, which aren't dramatically deep, they're like comic books but on screen. The archetypal character types (Reed is the over-thinker lost in his experiments who doesn't know how to be human, Johnny is the impatient hellion who loves experience and takes joy in doing, Ben is the tragic tortured hero trapped in a body that makes him a monster, and Sue... well, Sue fails the Bechdel test and is kind of the fourth wheel with unclear aspirations that don't involve Victor or Reed... just like the early comic, ha.)
Honestly, this is what I thought when I watched the film. I couldn't get that emotionally invested in the drama of the film but basically it's an amiable comic book film that is exactly what you would expect, with no imaginative or destructive turns of plot or character. It's pretty much paint by numbers. Even the comic book action with powers is exactly like what you might have seen in the comic, including some amusing turns by Reed and his stretching abilities, to the degree I was surprised they put it in a film. (And it was perfectly fine and even amusing.)
The Fantastic Four is an interesting group because they never did the secret identity thing. They were always celebrities and/or public figures. The film plays into that. Some of the Avengers are more covert -- if not secret identities, at least covert ones aside from Iron Man and Cap who were known publicly but could still manage to go undercover at times... not so for the FF, really. And this shows up in the film, where they are either mobbed on the streets or immediately hit the tabloids.
There's some things that still feel weird. Like, Reed and Sue don't really have any chemistry and I have no palpable understanding of why Sue wants to be with Reed. (At least with Victor, despite being a jerk, he's good-looking and rich when the film opens. Reed is like Victor but without the money, charisma, or ambition.) Sue's character also is underwritten, as mentioned above but also casting Jessica Alba and dolling her up all the time makes her this weird "pretty face" person when that kind of approach typically doesn't conform to her professional background. It all feels kind of fake. Likewise, it's not clear what makes Ben appealing to his ex, and it's not clear why Alicia falls for him. And so on. It all stays kind of assumptive and superficial.
Basically the film is "if you liked the 70-80's comic, watch this film. Nothing unexpected. Nothing screwy. Nothing too deep. Just exactly what you'd anticipate."