I wouldn't have an issue if that law was rewritten that way but the burden of proof would have to be just the student's word. That being the case it would be absurdly easy for the student to exploit any teacher he had a relationship with for a very long time or face being a sex offender. "You can't stop having sex with me or I'll tell the police you coerced me. Bang my buddy too or I'll tell the police you coerced me". I guess they could do the same thing now but the burden of proof point is still valid, we'd have to take the student at his word since the abuse of authority would almost surely be a private conversation between the teacher and student.
Apparently in this case, she might not have even been his teacher:
http://www.sacbee.com/latest-news/article185515568.html Busting teachers for position of authority over kids they have no authority over is crap.
I don't think you could write a law that used testimony of the victim as the only evidence required. I don't see why it'd need to be different than any other rape allegation. "Mrs. Brown said I had to have sex with her." "Then why are there a hundred text messages from you trying to setup a meeting time?" I do think there should be strong weight on what victim claims, but if there is other evidence that they aren't telling the truth it should be used.
As it stands now, a student could just as easily say "If you stop having sex with me, I'll tell!"
She is also being held on child porn charges over images he sent to her. This is kind of unrelated, but something needs to be done with the laws about teenagers send pictures they took themselves and people being charged with kiddie porn. I am not sure how you could change it without basically putting a huge loophole into the law. But if an 18 yo is banging his 17 yo girl friend he shouldn't go to prison because she sent him a picture of her boobs.