Hopefully I can provide a perspective on this. I have been both a science and humanities major; I started out in biology, switched to psychology, switched to Chemistry because it was convenient, then switched back to psychology. I started out on the B.A. track in psych before switching to a B.S. track. My general ed requirements, as opposed to chem or bio, included countless courses in philosophy, history, english, etc.
One of the biggest differences I have seen are the effects of being a humanities major as opposed to biology or chemistry. We have to read -- a lot. Not just skim through like we did in bio or chem, but actually read from cover to cover.
We have to write papers. I had to write 3 papers and read 3 books for social psych, on top of the exams. One of those papers had to be at least 15 pages in length. The textbook was around 600 pages, the novel in which I had to critique and review was around 250, and the supplemental book was around 100. Because of this, we learn so many skills that a science major would probably never learn; the skills associated with analyzing an author's text, deconstruction, writing an argumentive essay, etc. Coincidentally, these are all necessary skills to be a good physician as well as score relatively well on the MCAT verbal.
As a science major, I felt all I was doing was remembering facts and spitting them back out for an exam. Never was I challenged to think or analyze in the same manner as a humanities major does. In retrospect, I honestly believe I would have been handicapped had I remained a science major. Sure, saying, "I got an A in applied super-chaos calculus" may sound more impressive than, "I got an A in Contemporary Practical Ethics", but did you really learn any useful life skills? Probably not.
On a final note, some of the most intelligent people in history were not scientists -- they were philosophers and musicians. What does this mean? Probably nothing.