Is it really that many players?
UW had 8-9 guys in the playing rotation, and 6 were seniors. Only one of the rotation guys is transferring - Trevor Anderson (a Sr.), who signed at Valpo. 4 of the other 5 seniors are also leaving, but they are leaving college basketball altogether. We don't know about Davison yet, and the other rotation guys are staying.
There are also a couple of scout-teamers in McGrory and Hedstrom who are in the portal.
It is a total of 7 guys leaving, which seems like a lot, but it's pretty normal attrition when you break it down that all of this was seniors and scrubs. Maybe there were problems, but I don't see this normal-ish turnover as convincing evidence.