For my Why ND essay I spoke about how I originally tried to get recruited to the school athletically (for softball), however once i chose to not play varsity softball in college I decided to try to go for academics because I still loved it as a university. Then I spoke about how the opportunity of the Club Softball team is a good compromise between quitting softball and playing at a varsity level.
Could it be harmful that I only speak about softball in this essay? I obviously love other things about UND but I think this one is a bit different.
The topic is not risky but the way you answer it might be. The question is really about what does ND have that is not available at other similar colleges (club softball is everywhere), and why you feel it is important to you.
When my oldest was being recruited (not ND), the best piece of advice he got was to pick a college you would love if the sport went out of your life completely (it did). They look for people willing to get involved and contribute to the ND community.
Perhaps you could also include how you can transfer your love of academics and love of softball into something positive at ND - for example, perhaps you would consider coaching a girls team at a disadvantaged school? Or take the sport through a summer service learning project into a place without organized girls sports? Notre Dame can give you those opportunities, and the chance to make a difference through all your talents may be why you want ND to begin with!