Jail time is not the only punishment handed out in criminal court. There are fines, probation, restitution, community service, etc. The standard for burden of proof does not change just because the punishment is not jail time.

There are protections given in civil court that are not given at a university level. There are plenty of things that cannot be used as evidence in civil (or criminal) law because of the unreliability of said evidence. This would be things like hearsay. Not only that, but there is no independent higher body to which you can appeal if you think that the case was mishandled. These are both vital protections that are given in civil court. I would strongly prefer that these cases are handled even in civil court than at a university carried out by people who are not legal experts.

Also, I think that you are understating the impact that being expelled for sexual assault would have on someone. Expulsion could destroy all of the work that you have put into your education. Job prospects could be destroyed. Social networking could be destroyed. These have real, permanent consequences. Also, imagine the psychological and emotional damage that expulsion for sexual assault would cause. I cannot fathom how terrible it would be to live every day for the rest of your life with people saying and thinking that you committed a crime as heinous as raping or sexually assaulting someone.

Let me be clear that I am of the opinion that the punishment described above is absolutely deserved if someone did commit rape or sexual assault. I think that this, in addition to jail time, is well deserved. But imagine receiving this punishment if you have been falsely accused. This is a major, life altering punishment and we must take great care to make sure that it is not given to those who did not commit these crimes.