Not really. Is it more impressive to climb the seven summits, or write an original work and have it performed by the New York Philharmonic? These aren't cleanly comparable things (which was always the point, of course; the focus on "more well-rounded students" appeared when elite institutions were worried that academically successful Jewish students were becoming too big a proportion of the student body.[1])
You don't have to decide which is more impressive. What you have to decide is how much you want either impression to count for in your threshold score. Does high achievement count for 30%? 50%? 80%? Does it outweigh an utter lack of academic achievement (i.e. could a high achiever in the "soft" achievements hack it in the "hard" subjects, or vice versa?)
Once you've decided the proportions of things like that, this article proposes that it should be purely up to chance via lottery (an assertion I personally agree with.)
1: http://250.browndailyherald.com/how-1920s-anti-semitism-insp...