This "paradox" has bothered me for years: how fast should one run their easy days? You can make it very simple or very complex. I like to go complex and overanalyze so I say we have a lot of variables at hand here:
1. Individual variation between athletes (who is injury prone, who has more FT muscle fibers, who mentally needs to be challenged some days, etc).
2. Overall weekly mileage/volume.
3. Workout density: are they running doubles? Are they going hard/easy or easy/easy/hard? Are they hammering long runs the day after racing?
4. The types of hard workouts of course: how many tempo runs, how many Vo2max interval sessions (per season or training block of time).
5. Specificity of event they are training for. Since we are talking college team programs I assume cross country or 5k to 10k on the track.
So in a nutshell, with all those ingredients in the mix of an overall training program, one might put their "easy day" or recovery day pace in context. I've always tried to relax and run around 7:00/mile on easy days but a lot of my teammates at Hansons run closer to 6:00 and it seems to work quite well for them (in half marathon to marathon). I ran with some guys from Oregon a couple years ago and I know some of them run around 90-100mpw at an average of close to 6:00/mile (including faster workouts)