Not that it'll ever happen, of course. Fox is fully committed to continuing to make 'Fantastic Four' movies, and will remain so right up until the day they sign on the dotted line with Marvel Studios.
Look, I was rooting for Josh Trank. Won't deny it. I liked the idea of a different take on the FF, still do, even if he didn't stick the landing. But my point all along wasn't that this was going to be an awesome version of the FF and we should all embrace it, it was that it was okay to try something different even if it failed because the worst-case scenario was that they'd just reboot the property again. Because either Fox makes a new FF movie, or the rights revert to Marvel and they make a new FF movie. There ain't no third option here.
I'm assuming that we're going to see a Marvel Studios version, though, because Fox is getting to the same point Sony did with Spider-Man; they know they're not getting all the bang for their buck that they deserve and they can't seem to find anyone who can do the property right, but they also know that just letting Marvel have it for free is a chump move. They'll do a deal, and Marvel will be happy to agree because they want all their properties back under their roof and they don't have a ton of leverage--for all that Fox is probably going to lose money on this incarnation of the property, they can still make these cheaply enough to be profitable as a general rule if they want to just crank them out to satisfy their contractual obligations. So Marvel will lease back what they can't buy outright, same as with Spidey.
Which means we're going to see a new take on the FF set in the Marvel Cinematic Universe. What should it look like? Well, I'm hardly the first person to say this, but I think that the Fantastic Four really work best when considered as part of the era they were created in. They are steeped in a heady Silver Age brew of unbridled faith in science's abilities to transform society for the better, complete and total optimism regarding the future for the world in general and America in particular, and yes, jingoistic Cold War patriotism. So they should do what they did with Captain America--set the first movie in the year it was created.
So we're looking at the FF as Kennedy-era heroes. Not "super heroes", because this is the MCU and they really didn't have "super heroes" until Tony Stark held his press conference, but celebrities--Reed Richards, nicknamed by the media as "Mister Fantastic", and his amazing friends that journalists are already calling "The Fantastic Four". Known and lauded for their amazing achievement in reaching the moon with an experimental spacecraft of their own design and leapfrogging the Commies in the Space Race. Their "costumes" would be more like uniforms, jumpsuits that they wear when testing Reed's latest exotic inventions. They'd be famous, people would even know that they had superpowers...but one key element of their exciting story would be kept secret from the world at large.
Namely, supervillains. (After all, you don't really get superheroes until you get bad guys. Before that, they're just "cool dudes with powers".) My idea is that they work secretly for SHIELD, and its Director Peggy Carter. (Because Hayley Atwell is da bomb.) They deal with geopolitical threats too dangerous to even allow the wider world to know about, such as the mad dictator Doctor Doom, the subterranean tyrant known as the Mole Man, and Kang, the deadly foe from the future who threatens to enslave the human race, and who by all the evidence is destined to succeed. In fact, I'd make Kang the villain of the first MCU FF movie--not only does it get away from the whole, "Oh God, not Doctor Doom again!" factor, it also sets up the important factor in getting the FF involved with all the other superheroes...by the end, Reed Richards has time travel.
Not precise time travel, or otherwise you've just wrecked the storytelling engine--it's impossible to get closer than the right decade. But the first movie would end with Reed, Sue, Ben and Johnny realizing that the future is literally right there waiting for them. And that, they have to see. They time-jump fifty years into the future, ready to see all the wonders that exist in that brave new world...and pop out in the middle of the next Avengers movie, ideally right in the middle of the most dramatic fight scene ever where Earth's Mightiest Heroes are outmatched and desperate.
And what then? Well, allow me to quote one of the wisest sages of our era, a true Renaissance man with a deep appreciation for fine sculpture and fine food alike: "It's clobberin' time!"