Ideally what colleges should do is to use a standardized test and go strictly by the results of the standardized test. Standardized tests are not perfect, but if there are flaws in standardized tests then fix them, because it is better than the alternatives. The advantage for students would be predictability and being in control of their own destiny. Students would not have to apply to 12 to 15 colleges, instead the would apply to 2 to 3. The benefits for colleges would be better predictability as well. Today colleges use complex mathematical models to predict who is likely to accept their admission offers. Then they use "yield protection" to avoid admitting highly qualified students who are unlikely to accept admission offers. It is complicated.
Colleges can use complex data analysis to guess which students are likely to accept but hapless students can’t run data analysis to determine which colleges are likely to accept. Colleges, especially public ones, ought to minimize the guesswork and use more objective criteria to admit students. Students need to be able to control their own destiny through hard work. That’s only possible if guesswork and data analytics and so on is minimized.
Other countries such as UK use test scores for college admissions. At one time the US too used scores. But US colleges introduced subjective criteria ("holistic reviews") because far too many Jewish people were getting admitted when they used objective criteria. (Not kidding, see https://www.theatlantic.com/education/archive/2019/03/histor... ).
Even public universities perform complex gymnastics to decide which 4.0 GPA student to admit. Even when two students have taken the exact same courses (including AP courses) and have the same GPA, colleges do not consider them the same. (See here https://www.latimes.com/california/story/2021-04-12/covid-co... )