What Sankey is pushing for in the NCAAT is the same thing the B1G and SEC are pushing for in the CFB Playoffs. More automatic spots for their leagues, more of the revenue pie for themselves. Eventually, the other "power leagues" Big 12 and ACC will get shafted (we're seeing that in the expanded playoff model) and get even less revenue from the NCAAT and CFB Playoffs.
IMO, the NCAAT is single best event college sports has going. Better than the CFB playoffs. This isn't something the SEC and B1G should dictate. The magic of the NCAAT isn't about the big schools (though they invariably end up winning the most championships), it's about the Cinderella runs of small teams and lower seeded schools. You take more slots away from the smaller schools and lower seeded teams, and the less magic the NCAAT has.