A 911 call can't be cross-examined. If the person who made the call doesn't testify, the veracity of any accusations made during the call can't be explored via cross-examination. The question before the Court is whether hearsay statements made during a 911 call that aren't subject to cross-examination, because the prosecution doesn't put the caller on the witness stand, violate the Confrontation Clause. Cross-examination might expose the unreliability of a 911 call, and the value of testing an accusation through cross-examination lies at the heart of the Confrontation Clause.
Adopting the double-speak that has become fashionable in the 21st Century, the op-ed writers call this "evidence-based prosecution." It's more like "accusation-based prosecution." Having the alleged victim testify, subject to cross-examination, gives the jury evidence upon which to base a verdict.
The op-ed piece ignores the accused's right to a fair trial. That isn't surprising. If the assumption is that every person who alleges abuse has actually been abused, there's no need for a trial at all. The accusation suffices; guilt should be presumed.
The op-ed also assumes that a "victim" who refuses to cooperate has been intimidated by an abuser. This is surely true in some instances, but in others the "victims" don't cooperate because they aren't really victims. They often don't appreciate being told by "victims' rights advocates" that they are victims, whether they know it or not. Some accusers don't want to testify because they are reluctant to admit under oath that they lied to the police. The only way to sort out the truth is a fair trial, not a sham trial that depends solely upon statements made in the heat of the moment that haven't been subject to cross-examination.
Prosecutors always have the option of issuing a subpoena to a recalcitrant witness. If the witness don't say what a prosecutor wants the witness to say, or if the witness simply refuses to show up, that's life. It isn't a reason to argue for something less than a fair trial.
Victims' rights advocates are well-meaning (sometimes), but they too often proceed from the assumption that every abuse accusation is worthy of belief and every accused is an abuser who deserves to be convicted. Concepts like "fair trial" and "the right to confront" are lost in the desire to "protect victims." But whether an accuser is really a "victim" is what criminal trials decide. Sympathy for the plight of battered spouses is an insufficient reason to disregard constitutional rights that protect the innocent from unwarranted convictions.