At the same time, it's not a great selling point considering the horde of successful movies that are already selling that - especially Marvel films. Green Lantern sold that story and look how it turned out.
Really, though, it's Mark Wahlberg is gifted with amazing powers and so on - not some guy. He's probably the main reason it got any traction even with all the good will behind the original tv series. He's the main difference compared to the other movies - this time they got a real star who people already know and like to actually play the hero of the movie.
Chances are that he will either be an astronaut like in the original novel (though that's unlikely unless they have an active space program in this world) or he'll be a special forces soldier/secret agent already (like SHOOTER) and seriously maimed on a mission -- but he's too good of an asset to let go. There's really no reason they would just rebuild a regular joe and send him on missions.
In the original novel, it was interesting that they basically extorted him by saying that if he didn't work for them, then they would downgrade his prosthetics or not maintain them. So he was a reluctant agent who was actually a little suicidal in his missions at first.