Applying to college is like applying for a job – but without knowing what the job description is. The needs for a given college changes from year to year. So there is no clear way to know what you are “missing”.
Just do your best to paint a cohesive picture about yourself. Admissions people are busy, and if you have 20+ ECs which are scattered, it will make it more difficult. At best you’ll have 2-3 mins to make your point.
The application is not an autobiography. Don’t throw in everything under the sun. Figure out what makes you interesting, and align everything in the application to convey that same message. This is more about marketing and messaging instead of having the right ‘stuff’.