Fantastic Four was one of 2015's worst movies, and while some serious behind the scenes chaos caused that, it sounds like there was at one time a version of the reboot which would have made fans very happy. Before Simon Kinberg and Josh Trank rewrote the screenplay, Jeremy Slater was hired by 20th Century Fox to dream up a new take on the franchise, though he's revealed in an interview with Screen Crush that pretty much none of his ideas ended up making it into the version we got.
Explaining that his version of Fantastic Four further delved into the inner workings of the Baxter Foundation and the relationship between Reed and Victor, Slater says that the team would have encountered Annihilus (described as, "a pissed-off cybernetic T-Rex") in the Negative Zone and got hit by radiation giving them their powers. Victor meanwhile would have still been left behind, but he was going to kill Annihilus and use his cosmic control rod to create, "a sort of living body armor."
That sounds pretty good, but there's where things get really exciting for fans of the superhero team.
"In addition to Annihilus and the Negative Zone, we had Doctor Doom declaring war against the civilized world, the Mole Man unleashing a 60 foot genetically-engineered monster in downtown Manhattan, a commando raid on the Baxter Foundation, a Saving Private Ryan-style finale pitting our heroes against an army of Doombots in war-torn Latveria, and a post-credit teaser featuring Galactus and the Silver Surfer destroying an entire planet. We had monsters and aliens and Fantasticars and a cute spherical H.E.R.B.I.E. robot that was basically BB-8 two years before BB-8 ever existed. And if you think all of that sounds great...well, yeah, we did, too. The problem was, it would have also been massively, MASSIVELY expensive."
Basically, it sounds like Slater's vision was just too expensive, and a vision Fox weren't willing to invest in after the first two films didn't do particularly well at the box office. It's easy to imagine this version of Fantastic Four being a hit though, but given the failure of the last version, it wouldn't be at all surprising if the next reboot also ends up taking a grounded approach in order to save money...