There’s developing a spike in your EC’s and then there’s developing a spike in your curriculum. For colleges that have a recommended HS curriculum, it almost always includes X # of years of core courses (English, math, history/social sciences, science, and foreign languages) as well as arts for UC’s. Personal preference of the student does not come into play. For these colleges, there is no expectation or desire that an applicant be a specialist in HS. Even STEM-y schools like MIT and Harvey Mudd don’t suggest that students skimp on the non-STEM courses in HS.