The problem with the Tim Story versions is that they were too common denominator. They felt like they should be in the Kids section
There is a bevy of different relationships between the Four that can be explored: there's the romance between Reed and Susan, the siblingness with Sue and Johnny, and the rocky (groan) friendship between Reed and Ben, and at least one of these will play into the plot. There is also an opportunity to bring in more secondary characters from the Marvel universe, and maybe even do some crossovers with other movie franchises or Agents of SHIELD.
As for villains, Doctor Doom has been done, and Galactus / Silver Surfer has been done. Bringing one of them back would be seen as unoriginal, but forgiveable considering how much they were fudged up. It would be like bringing Venom into the new Spider-man series, but with someone who is actually suited to play Eddie Brock. If it were done right, it would be rated R, which I would personally love to see. Besides that, a Skrull war could work for a rebooted FF series, if that isn't already the plan for The Avengers 2.
Reed Richards aka Mr. Fantastic: Campbell Scott (The Exorcism of Emily Rose)
Or maybe Tim Robbins, or maybe William Petersen if he loses a bunch of weight. Scott was in a Marvel movie last year where he played the other Richard Parker, but it was a small role, and that has never stopped them before. Some may say that they're all are too old, but I would argue that Iron Garfield was in fact too young, and definitely lacked that "smartest guy in the room" presence. The Marvel cinematic universe needs a 'father-figure' leader who is more than just a military mouth, and Richards should be that guy. Listen to the upcoming Episode 3 of the podcast for more on Scott.
Johnny Storm, aka The Human Torch: Rob Mayes (John Dies At The End)
Chris Pine? He could work too, but I think people are staring to get tired of him. Mayes' personality in John Dies is tailor-made for Johnny Storm, maybe even Deadpool.
Susan Storm aka The Invisible Woman: Ali Larter (Resident Evil series)
I've had a thing for her ever since Final Destination 2. Who else could work: Abbie Cornish, Anna Torv, Amy Smart, other blondes whose names start with A. But not Alba.
Ben Grimm aka The Thing: Mickey Rourke (Iron Man 2)
He too was in a Marvel movie somewhat recently, but it was probably the most shallow and disliked comic book movie villain in recent memory. This could redeem Rourke in that sense. And besides, we're not going to see much if his face, and he's got the perfect voice for it when he's not doing cheesy Russian accents.