More than just individual routes, I bet DT was talking about route combinations. At a most basic level, you can’t run crossing routes when the WRs start a full field width apart, and there is a whole world of ways to time and adjust those routes. Because you’re not attacking 10-15 yards deep over the middle, WRs are spending less time learning to read a zone and sit in the hole. Route interactions, beyond switch/scissor routes on the same side, are less of a factor in Tennessee’s offense. Instead, the offense is designed to simplify reads to make defenses pick between defending the run with too few players or playing high-risk defense against deep passes.
None of these things are necessarily a big deal. No CFB offense is as complex as the worst NFL offense, and no WR shows up knowing what to do. NFL guys are drafting on physical traits most of the time. Any player with NFL ambitions should be spending time learning the game on his own, whether he plays in Knoxville or Athens or Columbus. College coaches are playing to win, not develop. They’ll only develop as much as needed to win.