Hornung is in both the College Football and Pro Football Hall of Fames, yet is overrated in your opinion. What is the basis of your argument - that Hornung was not as good as Jim Brown. Jesus man, Jim Brown is probably the greatest player of all time. By this reasoning, everyone who has ever played football is overrated because they are not as good as Jim Brown.
While not the greatest player in ND history - in my opinion that honor belongs to either Ross Browner, Johnny Lujack or Leon Hart, but Hornung was clearly one of the greatest players in ND history.