Because it will be adapted from the original comic book source. This could soften the blow for some people, but it also gives Spielberg and Smith some creative room to really tone down on the craziness of the story that made the original film so damn awesome. Filmschoolrejects got the scoop at a 'Seven Pounds' premier and here is what smith had to say:
We're looking at that right now. Not the film though, it's the original source material. There's the original comics of ‘Oldboy' that they made the first film from. And that's what we're working from, not an adaptation of the film...," said Smith.
I still don't like the idea. We all know everyone is going to compare the two movies in the end it's something they can't help. They can tell people that their version isn't based on the original all they want, but people are still going to compare the two.