Whitecat, Fitzsimons has a somewhat different running motion - even "labored" as you describe. But it might be effective for him. He is very pigeon-toed and that might explain his style.
There is a video out there of his anchor in the 4x800 at the New Balance outdoor championships in 2010. You will have to search for it. Same sort of rocking back and forth running style, but still very smooth - i.e., he is moving forward quickly and seemingly effortlessly. His time: 1:47.15. One might argue that he is an early bloomer, but one should not run worse than what one has already run - three years later. Personally, I have always thought he had a lot of potential. His ultimate future, though, might be as a miler, but he should still be an outstanding 800 man in college. Believe, at that same New Balance meet, he also ran an outstanding mile on the DMR.
Remember he was hurt twice as a freshman. Forget what the injuries were. Somehow I think it had to do with his back, but I am not sure..
Another reminder: he also ran XC in high school. Don't know what his training regimen is. And Marcus' aproach has less to do with mileage and more to do with heart beats.