Interesting post. I always think of pianist, Alicia De Larrocha as disproving the stereotype about long, thin fingers being the requirement to fluidly master the piano, from the technical side of things.
And it strikes me that Daniel Barenboim, from watching videos of his performances, has likewise small hands, but is a wonderful pianist and interpreter. My teacher, Lillian Freundlich, told me about Arthur Loesser who had unusually small hands as well. I think it's always of benefit to have a big span, to reach impossibly big stretches between notes as might occur in Liszt compositions, but that certainly is not the end all of piano playing. I guess I just don't get into the size of hands things, because, in my opinion, phrasing and musical expression are far more critical to performing a composition beautifully than any genetic, physical endowment.