It's a very common question, as most conventional windshields made by Rycote & other manufacturers have been spheres or extended spheres for a very long time.
The overall objective of the Cyclone project was to create a basket windshield system, that achieved at equal of better wind reduction to that of a Modular windshield + Windjammer, but with the transparency of a Modular without a Windjammer. We achieved this and went beyond our hopes by changing the shape, and developing our new fabric 3D-Tex.
The reason for the shape change in the Cyclone comes down to this choice of materials for the structure. Any time you put a mic in a chamber, there's a chance of hearing the room tone that the reflective surfaces create. So the Cyclone moves away from flat or parallel surfaces, to reduce the impact of this room tone affect.
The structure of the windshield (underneath the 3D-Tex) is critical to the overall performance too. The openings on the basket are as open as possible to reduce reflective surfaces, and therefore improve transparency. However, this being a Rycote product it's tough enough to withstand years of aggressive use in the field and of course light enough to hold on a pole all day on set.