I don't think the comparison of McD to Johnny is fair. ISU basketball was in a deep hole when Johnny took over, and it was still an era when the "haves" like UCLA & North Carolina had big advantages over the have-nots. Nowadays, you can see a team like Butler scrap & fight all the way to the NCAA Finals.
Plus, No matter how badly Johnny's record sucked, at least he managed to create "Hilton Magic". GMac came into a program where most of the hard work had already been done for him, but Johnny had to build it all from scratch.
All in all, you make a good point with the comparison, but I think there are enough minor differences that we shouldn't start trumpeting GMac as "the new Orr".