By "philosophy" I mean a broad meta study of the field: the philosophy of science, epistemology, the philosophy of religion, the philosophy of language, etc. By "rhetoric" I mean both the construction and execution of persuasive argument in printed and verbal form. Everybody should have a few folks from history that they are intimately familiar with and feel that they faced similar problem in life.
Philosophy can give you a broad view of what is knowable, what is not, and how folks move from not being able to to know, to being able to know, to actually knowing -- a key component of both the advancement of science and the development of an individual. Topics like stoicism and existentialism, if presented appropriately, can provide a backstop of beliefs for any student, regardless of their religious or moral convictions. Rhetoric helps you spot when folks are trying to manipulate you, and it challenges you form coherent arguments yourself about things outside of one small area. History gives you context: every generation feels as if it is here at some kind of special and unique spot. Knowing that humans 500 years ago were the same model as the ones you meet on the street helps put your opinions and interests in context.
Unfortunately, if I hadn't defined what I mean by those three subjects my recommendation would be pointless. You can go to any college today and take courses under those headings and not receive those benefits -- perhaps this is because those who design the courses view them as introductions to a deep dive on a topic and not practical, broad, benefits-based interventions with young minds. I don't know. I understand that my advice is easier said than done: how would you introduce history to a large group of students in such a way that each student found their own historical figures that they would benefit from absorbing? How do you take topics that the students might find popular and feel-good and give them the ability to tear apart the fluff around them and find the good stuff underneath? Having a professor stand up and say something like "this is my opinion on X. I may be wrong, but we'll never know unless I give you the skills to identify and refute faulty argument" just isn't happening. Instead, classrooms are hierarchical affairs.
Instead of this discovery process, students get pre-canned little happy meals. Instead of taking charge of forming their own identity across multiple disciplines that they can describe and defend, we get these examples of kids simply being out of their depth once you stray just a little bit from their established path. An education that is both broad and self-determined is not an easy problem to solve. The system is not built for it.