You proved the main problem of DNF in one song. Bravo.
Here was the real issue (besides the loading screens):
It's not that Duke doesn't fit into today's society. It's that his personality and his gameplay have always been linked. In Duke3D, Duke didn't just say he was badass: he was badass. He was carrying about 8 heavy guns around and still running at the speed of the cheetah. He was kicking with both feet at the same time while still moving forward, propelled by nothing but his awesomeness. He was taking on 10 aliens at once and still kicking all their asses, making lewd comments as he did so. He had a FREAKING JETPACK.
In DNF, he still acted like he was all tough, and I love Duke's personality, but he was a wimp: taking cover, only being able to take about 4 hits before dying, only having two weapons, etc. It was like Duke Nukem's atmosphere with Call of Duty's gameplay, and that doesn't feel right.
On the bright side, knowing what the fans want, they can hopefully listen to the complaints and return Duke to his former glory. At the beginning of the new Duke game, he should spit out some gum, look in the gum package, and see no more. He should then look at the camera and smirk.