The SAT isn't perfect and you can prepare for it (to an extent), but its alot better than GPA or any other measure as atleast it's consistent between schools.
It was actually introduced to help be more egalitarian and meritocratic. And its been shown to correlate pretty well with general purpose IQ tests as well as later success in life.
Removing it will no doubt help them discriminate more against asians and jewish people. they introduced meritocracy and it produced a result they didnt like for certain races so theyre removing it.