I have had my players perform what you are referencing since I began coaching at the high school level and I firmly believe in the efficacy of this form of exercise.
There are many options.
In addition to the known benefits of ‘tempo’, per what I reference in the DVD, are the development of the oxidative properties of the musculature involved in the competition exercise; particularly via the performance of the competition exercise as sub-max intensity. This is a principle that has long since been proven by Charlie and Bondarchuk, to name only two.
So not only are you limited, regarding receivers, to running complete routes at sub-max intensities; but also the repeated performance of segments of routes in a fashion that satisfies the intensity and work:rest intervals consistent with extensive or intensive tempo (depending on how the programming is structured) and even more specifically the varied heart rate intensity ranges of the anaerobic threshold.
Don’t be concerned about the difference in the rhythm/feel of the routes due to the sub-max speeds. The sub-max speeds are no more detrimental to the performance of the full speed version as linear tempo is to the sprinter. In fact, I view the sub-max intensities to further support the development of the competition exercise from the standpoint of indirect transfer.