I am reapplying, and I do not think that my secondary essays the first time were my weakness. I realize that, at the same time, it will look lazy to submit the same secondary essays. I am trying to rewrite them now. However, even with the added 2 years of new experiences since my first application, I am finding it incredibly difficult to rewrite the answers to the same questions. In fact, I think that by forcing myself to change them, they are becoming weaker than the essays I submitted the first time. Does anyone have advice to offer? I spent significant time writing them the first time around, and I feel like I squeezed the best and most valuable insights out of the experiences I used the first time. Now, I am forcing myself to use experiences which are lesser quality.
It depends on the prompt. If the prompt is asking about something that is already set in stone, e.g. childhood hardships, poor grades, socioeconomic diversity (race, income, LGBT status, etc.), undergraduate experience, greatest challenge (if you overcame significant hardship as a child, e.g. fleeing war, immigrating from another country, etc.), then reusing the same essay and topics with only minor changes is very acceptable IMO. You should not be forcing yourself to use less meaningful experiences.
However, I would hope that with two additional years of activities, that you can draw upon more recent experiences to answer/supplement at least some of these secondary prompts, e.g. diversity (highlighting a particular strength or uncommon feature of your application that you've fostered over the past two years), future career plans (again, incorporating what you've been doing over the past two years), personal characteristics, etc. For example, as a non-trad, your example of leadership should not be something that happened as a freshman in college for a school project (again, barring uncommon circumstances).
Unless there is truly no way to improve your secondary application (which is doubtful), there should be some changes in some your essays reflecting the growth you've had over the past two years. The above also holds true for the primary application, especially your personal statement, except for experiences that have long since concluded. It would also be wise to apply to new schools as well. Just my thoughts and best of luck.