It sounds like you an unreasonable bias against the school. 15th to 12th is a HUGE gain. Very few schools who are in the teens move. Take Cornell and Brown for example, they have been 14-16 for over a decade.
Us news isn’t a main factor but it gives you a point of reference. A degree CAN be diluted at a larger university. At large schools, it is more difficult to accommodate the students’ needs than smaller ones. Certain classes are tough to get, less established teacher, and less individualized attention, just to name a few.