The problem with that is that even the makers of standardized tests don't recommend overemphasizing the test scores and as you allude to, GPAs from different schools are directly compatible.
I know that the undergraduate admissions offices come up with a predictive index based on each applicants test scores, grades, and high school. Law schools, if they don't do the same, could. There is no necessity to base admissions on soft criteria like interviews and how enthusiastic are the recommendations.
If I was in my state legislature's education committee, I simply would not trust the people in charge of our state university to treat conservatives fairly in either admissions or hiring. With hiring, it is tough to do something about. But in admissions, why not a push to mandate objectivity?