Completely agree with most of the above, however, I would add this:
I've definitely derived personal and professional benefits from being at a school affiliated with a strong pediatric residency and tertiary children's hospital (although I plan to go elsewhere for residency) and with an excellent program in my intended subspecialty (pediatric hematology/oncology). I took these factors into account when I decided where to apply and of those things that were important to me in choosing a school four years ago, this is one of the few that has really panned out. Curricula are often not as innovative and brilliant in practice as they are on paper; your classmates may not be as warm, welcoming, and seemingly well-balanced as the older students you meet during your interviews; relationships that kept you in one geographic area can quickly change.
That isn't to say these things aren't all still really important - they are and I would take them all into consideration again! But my med school experience was profoundly shaped by my interest in pediatrics and pediatric hem/onc, and the access to those fields that my med school provided. I was able to spend more than a third of my third year on pediatric rotations, including half of the surgery, neurology, and psychiatry clerkships. In my first year, at my request, I was paired with a mentor in peds hem/onc, with whom I've attended rounds and clinics throughout my med school career. She also allowed me to take charge of a research project in her lab, which led to a publication and poster presentation. Although I'm only halfway through the interview process, the depth of my experience in peds hem/onc and the "maturity" of my career interests has been remarked upon repeatedly (and positively!). Plus I'm frequently assigned to interviewers in the hem/onc department, who usually know my advisor and the other attendings that I've worked with.
That's a very long way to say: Don't discount the benefits of attending a med school with opportunities in your subspecialty interest. They do exist.