Good news about GWU, but I highly doubt that many US schools will completely turn away from SATs/ACTs. Even GWU has only gone 'test-optional', so I would bet that most of the top candidates will still be taking those tests and submitting their scores to GWU.
I definitely don't envy the job of the college admissions officer. It must be very difficult to make cuts between hundreds of almost-identical applications while also trying to fish out applications of exceptional students who (for whatever reason) have weak application packages. In an ideal world it might be possible to interview all of the candidates, although that opens up other potential biases. At the end of the day, the SAT/ACT is just another way to try to distinguish between slightly worse and slightly better candidates, although, as the article points out, it isn't actually particularly good at doing so.
One of the other issues with the SAT/ACT is that it furthers gaps between the 'haves' and the 'have-nots' when it comes to higher education. Sure, everyone writes the same test, regardless of their parents' socio-economic standing. But whether or not a student gets prep books, group (or private) tutoring, gets to retake the test (at about $50 a go, iirc) to improve their score etc. is all highly dependent on their parents' expectations and financial resources.