I think you both are over selling the speed improvements seen in college. Getting "straight-line" faster isn't necessarily a huge part of a college S&C program. Most kids coming in are already excellent athletes and for many speed is already a trait that is fully developed. Try and think of the last recruit to come in with questions about foot speed who has developed speed into a strength by the end of his career. For all but DBs and WRs, football is about quickness and explosiveness. That's where your S&C programs focus their energies and that's why guys add weight. While adding 30 lbs of muscle might not necessarily slow one down, it would be highly surprising for anyone to actually get faster with that extra weight.
Hoke was top notch at this aspect of his job.