In that other comment you said "If there are preferences, they're nonobvious, and it's not clear how you would go about discovering them."
Well, there is a large and well-developed industry of getting high school seniors into colleges. There are a lot of people who gave a lot of thought to the issue of how to present the best image of an applicant to the admissions office. These people write books, give seminars, offer consulting, etc.
The issue of "correct" extracurriculars is extensively discussed. Some of the people discussing them used to be admissions officers and now work in the college-advice industry. As far as I know the general consensus is that extracurriculars matter. Not enough to compensate for bad grades or low SAT, but if you're applying to a college that's in the right range for your grades/SAT, the extracurriculars matter a lot.
You seem to be ignoring what is, basically, existing literature, and putting out your own recommendations on the basis of several conversations that you -- as a member of the public -- had with several admission offices. Are you quite sure that you understand the issue in sufficient depth to give advice to other people and maybe even charge for it?
(I'll add that posting to LW is one way in which we're vetting our research and advice.)
[Edit: The post below gives the impression that our conversations with admissions officers are our only reasons for believing the claims. We've also consulted with other sources such as How to Be a High School Superstar: A Revolutionary Plan to Get into College by Standing Out (Without Burning Out) which corroborate the admissions officers' remarks]
We spoke with admissions officers at Harvard, Yale, University of Chicago, Columbia, Stanford, MIT, Duke, University of Pennsylvania, Dartmouth, Williams, Johns Hopkins, Swarthmore, Brown, Northwestern and Caltech, about how they evaluate student participation in extracurricular activities, for 15 colleges total. Some things that we found based on college's statements are below.
Kawoomba suggests that colleges' statements on the first point below can't be taken at face value. What do you think?
Cross-posted from the Cognito Mentoring blog
See also High school extracurricular activities: factors to consider and College statements about extracurricular activities