So... let's see... if play as one team, you're stuck playing only one game per week and this fails.
If you're playing all the games, it also fails, as there's no sim stats involved.
So, this is good for people that play one or two games a week, bouncing around between teams who somehow still want "real" results despite the games they play obviously varying away from reality. What happens when you get to playoff time and you win a game that was lost in reality? Yeah, no more DNA.
What we need is AI smart enough to adjust strategy based on situational awareness and the teams & players involved, with the real life counterpart being a base to start from.
The NFL doesn't have enough games for this DNA thing to be worth using. By the time you get enough info to actually start accurately predicting how each team is going to play, the season is almost over. That's why every single sports game fails to accurately simulate it's current season. It's always based on the year before. Show me a single simulated Madden 10 season that has the Titans winless to this point. It's not going to happen.
The best you can possibly hope for would be a post-superbowl patch for the first season to use the real results and a final roster update to have all the player ratings as accurate as possible. And once again, it's only good for one season. As soon as you get to year 2, it's all fiction again.
Just play the freaking game. Yes, we all want realistic results. Realistic doesn't mean identical.