@oristarA,
I think it is interesting handwriting: it reminds me of my own, and may have developed over the years in the same way my own did. As a child, I learned what they called the Palmer Method handwriting, and I did well enough in those classes, getting all A grades. The teacher was probably a bit kind on those grades. In my twenties and thirties, I turned to art as an interest, and as part of that took up calligraphy and sumi-e painting. At the same time, my work life got more and more hectic and there was necessity for writing fast. My field of work changed in that after some years of study I became a designer who did a great deal of hand drafting and lettering, almost always under short deadlines.
At one point, my writing and printing both had two types, depending on the project or part of the project: presentation style, and quick note to a colleague style. My quick note style is what reminds me of Hillary Clinton's writing above - it was a mix of printing and writing letters, and included some elements of artistic flair.
As I age I no longer do any hand drafting and I've settled into my quick-note handwriting style as the only way I print or write. I like it better than my old efforts at calligraphy or Palmer Method script; I like its idiosyncracy, and it is still usually fairly readable.
I have c0llected some postcards from the early 1900's and the english penmanship in those is often exquisitely beautiful. While this is true, I am presently more interested in more individualistic handwriting.
Hillary was a working attorney for quite a few years. I would bet she has written a lot of fast notes. I see some art in her style, and wouldn't not call it crappy.