I do think studying historical types is tremendously helpful for type design. (I also subscribe to the idea that designing types is tremendously helpful for researching type history.) With enough study you start to develop a more interior understanding of why letters look the way they do — not just ‘I’ve seen enough fonts to have a sense of how wide an S should be,’ but rather ‘I’ve come to understand that in this genre of design, underlying simple geometry (or an impulse to even out cap widths, or an overriding focus on equalizing counters, or etc.) dictates how wide an S should be.
–Craig Eliason