My initia reaction was this was a desperate move. It may still turn out to be that but ultimately, it's a short term win at the worst for both parties.
Wichita State had made 1 tourney in 20 years prior to the arrival of Gregg Marshall. Initial blush makes you think their recent success is coach driven. While his presence has helped make them successful, we have two examples of how a mid-major can sustain with one coach and with multiple coaches.
Gonzaga made a Cinderella run with Dan Monson and then Mark Few came along and grew on that magical March. Despite many offers at more prestigious places, Few stuck around and turned the Zags into a national power despite league affiliation. In the Midwest, Butler did the same running through many coaches. Marshall can stay at Wichita and be another Mark Few or Wichita can sustain without him. Both are doable. Either way, the Shockers are in a better position to sustain where they are and even exceed. Also, Gregg Marshall has a lot more reason to stay.
As for the AAC, it was a shot worth taking. The league has plenty of good basketball schools that are simply in a period of flux. The league can be very good. They also have to be realists. UConn & Cincinnati will always be expansion targets. While the Shockers don't have D-1 football, rumblings are they want to work their way to that point. Also, they have the Koch Brothers willing to spend some $ on them.
The loser is the Missouri Valley. Once the shining beacon of the mid-majors, they've lost their most rabid fan base in Creighton and their most marketable team in Wichita State. Rumored Shocker replacements Valpo or Murray State are very good basketball schools with success stories in their histories but it seems like decades since the Valley looked like a 3-4 bid league. That's too bad in this new world.
When Wichita State go their 10-seed, this was fair accompli. They had no choice but to make this move. The big shots in college athletics will be happy as well as it continues to weaken the mid-majors. Understandable series of events. Also a sad series of events.