Here’s the thing, too: sexual assault is a crime. Universities shouldn’t even be investigating crimes at all. That should fall to law enforcement. And, if a conviction is obtained by the appropriate authorities (who do have the power to compel testimony and such), then the university should impose appropriate punishments, up to, and including expulsion or revocation of degrees.
Would you really be comfortable with universities having that power? This sounds like something law enforcement and courts should handle, not an institution for education. This should be completely removed as a capability from the educational institution.
Until universities can compel testimony and subpoena evidence from everyone, including non-students/employees, they can’t have fair proceedings.
Until they have that power, they should be severely restricted in what negative negative findings they can make.
An accuser/accused who had to beg people to testify in their support isn’t likely to get justice.