Random Curiousity, I took ISU's RPI of 31 and dropped their 3 games against WSU. Their RPI went from 31 to 38.
Though if WSU left, they would backfill WSU with someone else. UMKC has been rumored before and they are a middleish of the pack RPI (180). So I took ISU and changed the W/L/L to WSU over to UMKC. RPI Jumps to 49.
Though most likely, ISU would probably sweep UMKC in the regular season. So I ran that. Put W/W/L for ISU vs UMKC and their RPI is 42. So a 28-5 (18-0) ISU would lose 11 spots in the RPI compared to a 27-5 (17-1) ISU with WSU on the schedule.
Just some random thoughts on how it would ripple through the league.