Are the Fantastic Four cool? I don't think so. I don't think they are edgy or dark or, to be honest, likable or heroic in an archetypal sense - they're too flawed. What makes them an effective superhero team is that they're dependant on eachother to accomplish anything. Reed Richards likes to work in solitude, Sue Storm-Richards is often described as having potential to be the real powerhouse heart & soul of the team, but while she does have her moments, she is not Wonder Woman. Johnny is a giant dork who thinks he's cool, but always runs the risk of being a fatuous phony. Franklin is the wild card - one moment, he's this ordinary, sometimes saccharine Beaver Cleaver-type, the next..he might as well be a djinn. Valeria thinks Doctor Doom is a cool guy and would probably leaves the back door open for him to crash family events. Namor is the myopic homewrecker. As for Victor, he's the guy who has everything, but not exactly to his liking.
And then there's Ben - The Thing. This guy can hold his own against The Hulk, knows how to fly rocketships and has a college education..yet he likes to downplay his intelligence, which is interesting..but never explored much.
All these characters play off eachother and are dependent on eachother...but they are not The Incredibles. That lazy analogy keeps coming up and bores me because the Fantastic Four have a much richer, varied and interesting world than the one depicted in that Pixar film.
I have a theory that nobody really knows what to do with these characters, which is why I'm convinced we've seen a lot of boring/unremarkable/awful comics, cartoons and movies with them. I think it's because the Stan Lee and Jack Kirby run is so highly regarded that the book stagnated and went out of gas, creativity, although John Byrne and Walt Simonson's respective tenures do have a lot of fans. But the consensus, "If it ain't broke, don't fix it!", has resulted in either crude pastiche or grotesque reinvention, appealing to fewer people each time. Consider how Doctor Doom was once regarded as one of the greatest comic book villains, the inspiration for Darth Vader, even - yet his portrayals on film have cast him as a roadshow also-ran. Sailor Moon could beat him up.