This is the simple, fair & transparent solution. Determine threshold requirements based on a combination of tests, grades and courses taken. This might produce many more qualified students than places available. Then do a lottery.
There is no such thing as a “whole person” at 18-years-old. Any attempt to be more precise in assessments is silly and invites bias and corruption. Keep it simple and it is harder to cheat.
Almost all kids who want to go to college can go to college today. The problem comes from the artificial scarcity created by the “top” universities. A lottery addresses this. It also makes the kids less crazy competitive and would make them less hierarchical.
Consider that today if a kid is rejected by a university, she feels personally aggrieved, maybe suspects cheating. The lottery would not eliminate the sorrow, but it would mitigate the anger and the hurt.
I feel strongly about this and have articulated it for years in more detailed form. IMO, the big reason we do not eliminate the anxiety in admissions is that too many benefit from it.
One more thing. Consider that those kids that got in through the dishonest procures discussed in the recent scandal evidently did okay in those “competitive” schools. Some have already graduated. What does that say about the emissions process? Beyond the threshold requirements, it is not better than random chance, just more anxiety causing, expensive and opaque.