Like has been mentioned, people just LOVE to jump on the bandwagon to say that Bush can't be an everydown back.
What most people are forgetting is that Bush gets the ball a lot more than just on runs, and Bush actually averaged as many touches per game this year as many as the top NFL RBs including Alexander and Tomlinson.
Bush had 283 touches in 12 games = 23.58 per game
LT had 390 touches in 16 games = 24.375 per game
Alexander had 385 touches in 16 games = 24.065
So LT and Alexander averaged about half a touch more per game than Bush, which would be about 8 touches over the course of a season. And keep in mind that not only are LT and Alexander feature backs, but they're some of the most highly worked feature backs. This year Bush averaged more touches per game than many NFL feature backs.
Mcgahee had 325 touches in 16 games = 22.0 per game
Rudi had 360 touches in 16 games = 22.5 per game
Steven Jackson had 297 touches in 15 games = 19.8 per game
And that's only the tip of the iceberg. Now granted, Bush would have to play an additional 4 games in the NFL (16 vs. 12), but it wasn't exactly like Bush was struggling to stay healthy with that amount of touches. Heck, plenty of feature running backs in the NFL don't make it 12 games with even fewer touches than Bush is getting, yet Bush got as many touches as the people getting the most in the NFL and was as close to the picture of perfect health as a RB touching the ball 24 times a game can be.
I think some of the elite LBs can run that, but I did exaggerate to make my point. However, I think it is still very valid. The NFL defenders are faster than the college defenders and the RB is not going to get noticably faster when he goes to the NFL. His advantage in speed will shrink.