So, I saw Fantastic Four today with my nephew. Wasn't the worst movie I ever saw, but it wasn't great either. First of all - it's not as bad as the internet would have you believe. The first half felt like it was mostly lifted from the Ultimate Fantastic Four series. In 2000, Marvel Comics started the Ultimate line, which was a fresh take on their heroes, set on an alternate earth. It was the idea that these origins are happening now, instead 40-50 years ago. There have been some really good stories told in the Ultimate line.
Second half... that felt rushed - especially the (anti) climatic fight scene with Doom. Doom was probably the worst thing about this movie. Before getting powers, he really didn't serve a purpose. After powers, he behaved like Annihilus with Blastarr's power set. The action part of this movie just really didn't seem to fit the Fantastic Four, though the ending was fine. There was no after-credits scene (a Marvel movie staple), which was a let-down.
There were other little things that bothered me as well - Thing not wearing pants, for example. The casting was fine - none of these actors will be THE definitive version of the characters they portrayed, but I didn't feel let down by them either.
Here's the real trouble... I do go into a movie (or tv adaptation) with the idea that it's an alternate version... It's not the main comic versions, but their "Earth-TV" counterparts, if you will. X-Men showed us how good comic book movies could be! X-Men, the first Spider-Man movie, Iron Man, Thor, Captain America, Avengers, and even Ant-Man... while they may have strayed some from the source material, they remained true to the spirit of it. To do Fantastic Four justice, you have to dial into Stan Lee and Jack Kirby's version of them! That is the definitive Fantastic Four! The movie failed to do that.
I'm not sorry that I saw the movie. My nephew (who had the same "meh" reaction I did) and I had a good time! I just wish this had been done by Marvel Studios... they would have hit a home run instead of striking out.
BTW: We saw FF on a Sunday, at a similar time-slot to when we saw Ant-Man a few weeks ago. There wasn't even 25% of the crowd there for FF as there was for Ant-Man.