How much personality should come through in a college admittance essay?

My wife is currently applying to the University of Washington Business School and is writing her admittance essay. I think her essay sounds really good, however it is very business oriented (I don’t see a lot of her personality coming through). As an art school grad I don’t have much experience with traditional college witting and am curious if it is more beneficial to get personal with the admittance essay or if sticking to the facts will do the trick?