So here's a suggestion, tell the admissions offices that they are inherently suspect, much like was done to Southern states regarding civil rights.
Tell them that they may promulgate whatever admissions rules they want, with several provisos:
1. All of the metrics MUST be quantifiable, and judged independently
2. All of the rules for selection MUST be published and publicized at least one year before implementation
3. Civil service/tenure protections for all employees in said departments are hereby revoked permanently. If the public doesn't like your definition of merit, they can fire your ass at will.
Basically you can set the rules however the hell you like, but they have to be totally transparent and as nondiscretionary as is practical. You also have to be able to defend them publicly without any institutional protection.
So, if you thought that you wanted to avoid too many pencil-necked grinds, you could add NFL combine-like metrics to your selection index. 40 yard dash time, maximum press of whatever type you like, 30 mile march time, whatever you like.
Say you want leaders or joiners? Ok, you can give points for leadership positions in organizations, you can even scale it according to the size of said organization if you like. But Model UN and FFA and JROTC all have to be on the same scale.
Say you want an attractive student body? Ok, you can include things like BMI, 'Hot or Not' Scores, or the like. But any discretion (as is the case in 'hot or not') must be your own.
Say you want academic or artistic excellence? You can give points for placing in various competitions, for gpa, for SAT/ACT scores, or the like. But guess what, you have to publish EVERY jot and tittle that you use. Your formulas have to be published and have to be computable by anyone who can use an Excel spreadsheet.
Say you want large alumni donors? Fine, but the amount of dollars to points has to be laid out EXPLICITLY, and guess what, you've got to defend it in public without institutional protection.
No holistic bullshit. Transparency, accountability, and no discretion involved.