Okay-- would you have preferred if I'd stated:

applicant I is "well-rounded, and possessed of a lot of varied EC's indicating soft skills" and applicant II is "pointy but no indication of soft skills" all other things being both equal and equally desirable?

That's really just two factors-- global ability versus singular, niche type ability, and the things that EC's are ostensibly about to begin with, that is, those elusive soft skills that matter outside of academia.

If those two applicants are equally capable on the SAT, then what?

Please note-- I didn't say (nor imply) that this is the only two types of students who DO apply. Merely that the archetypes are reasonably representative of at least some students applying to such institutions. Perfect test scores are nothing like an entry ticket to an elite institution these days.

I also know which I would argue for (and did)-- but I admit that there is an argument that can be made for candidate b, as well. Candidate b may well have greater potential as an outlier, all things considered. It's just that such people may or may not positively contribute to the educational environment for their peers at an institution. KWIM?
Schrödinger's cat walks into a bar. And doesn't.