Chuck Long was a terrific college QB, and most years he did not have such a great supporting cast. His main WRs were Happel and Helverson, or Dave Moritz, and Robert Smith was fast but had stone-hands. Chuck had good TE's, but TE's weren't used like they are now. He had Harmon as HB, but really only for one full season, the rest of the time it was other lesser guys, though Owen Gill was a solid back.
In sum, Long's supporting cast was good but not great. Rumor was that when he was an asst at Iowa that he spent a little too much time with his family and on the golf course, and Ferentz declined to invite him back. I don't know first hand if this is true, but that's been the story for many years.
AT SDSU, Long also was canned and left it in a really weird way. I may have the details wrong on this, but I remember reading that he was kind of fired, but could still draw a paycheck as long as he showed up for work (or something like that), so he just kept going and going in to work even though he basically had no job and nothing to do. I thought it was really odd at the time, and so did a lot of other people, who I think lost respect for Chuck because of it.