Many sex abuse cases are of the “he said, she said” variety because when an actual offense occurs, there’s usually only two people present. To ask for two or more witnesses to these types of crimes would be letting a lot of actual offenders off.
Although I do recommend prosecuting false allegations, it has to be done with the utmost care. A lack of conviction does not necessarily equal a false allegation. Once someone is accused of a false allegation, they need to have the rights of any accused as well. This should be a civil penalty as well if found guilty. The person who was accused of a sex crime just had their life turned upside down and their reputation is forever destroyed even without a conviction.
The laws on this would have to be carefully written so we can minimize actual or even perceived victims being accused. A false allegation should only be prosecuted if it’s proven to be a completely bogus claim. I also think minor victims that purposefully seduce older sex partners should be prosecuted in juvenile court as well.