I was just answering a question about how admissions are done in other countries. I wasn’t suggesting that the US could or should go over to national school-leaving tests. In fact, IB students do already participate in a form of this system, and NYU accepts IB exams and national school-leaving tests in place of the SAT/ACT. Whatever the merits or demerits of this idea, wholesale substitution of national school-leaving tests for the SAT/ACT would require a national curriculum, so it couldn’t happen in the US.
I don’t know whether the Japanese system to which you refer includes oral examinations or interviews by professors for short-listed applicants. These are relatively effective in reducing cheating as well as moderating the benefits of excessive prepping. However, I think it is pretty useless to tell universities to significantly change their admissions systems because short of legislation compelling them, they won’t.
My opinion is that the universities have the system that they want because it is the universities that put that system in place and control it, including the nature, content, and mode of administration of the SAT/ACT. The universities just don’t want the negative PR that sometimes comes with that system. So the scandal may yield some minimal changes to improve public image, but unless there is a public outcry for legislative intervention, we won’t see any meaningful changes in the transparency of the admissions process, or in the content, use, or even cheating opportunities of the SAT/ACT. The opportunities for cheating have been discussed at length in the SAT/ACT threads, and they will remain even if there is crackdown on the cheating-for-the-0.1% in the Singer scam.