Why give him the name of the FF's arch-enemy if you're changing the character? Victor von Doom and Reed Richards were college roommates before they became Doctor Doom and Mr. Fantastic, and the enmity from that time has always been a big part of the story.
More, it seems like a "hacker" is a disappointing enemy. The Fantastic Four have usually fought mad scientists, aliens and cosmic foes. They go into space and alternate dimensions more than any other Earth-based Marvel character (aside from maybe Dr. Strange and Agent Brand's troops on the SWORD station). If they won't use Doom (and I understand the decision not to use Galactus) then why not the enemy from FF#1, Mole Man bringing his monsters up from the underground? Why not Skrulls?
They're the Fantastic Four. Pitting them against ordinary humans loses the idea of what has always made the FF special.
Edit: I was previously rooting for this movie to succeed. I'm one of the few who liked the first two FF movies; for all their faults they at least tried to stay close to the characters (until the Galactus fiasco). I was just barely willing to give them a chance on explaining how Johnny turned black, but if they're gonna shit all over Doctor Doom, arguably Marvel's greatest villain, forget it.