Over a 4 year period of time that gives you 15 above the the 4 year limit and plenty of room to accomodate the various vagarities such as injury, transfers, early entries, etc.
I could perhaps see allowing perhaps a two year exemption in the case of a new head coach to maybe 28 since there will always be kids who don't fit in with a new staff.
A side benefit would be further dispersion of talent if that is what the NCAA is seeking.
