I think the Prosecution did get a three run Homerun though, with the audio tapes of his confessions to his mother and his wife.
I believe the jurors heard him in his own words, in his own voice, under no duress, speaking to the 2 people he loves the most, and sincerely confessing his worst sins. He bared his soul to them.
On top of that, his voice was then compared to the voice of BG, and they sound like a perfect match, according to many who were in court.
So after hearing those confessions, I think the jury will be more likely to accept the confession that Dr Wala testified to. That confession was bolstered by the info of BW's white van actually being right there on the gravel road and interrupting his sick crime. Just like he reportedly described it to his therapist.
She was absolutely unprofessional and deserves to be fired---but you don't have to pour the baby out with the bathwater. IMO