Regarding keycap thickness in general, the degree of thickness is not necessarily correlated with quality or performance, although psychologically at least, there seems to be a threshold of thickness below which confidence in the product wanes.
An example: Recently, I pulled the dye-sub PBT caps from an IBM P70 Alps plate spring keyboard, and I discovered that the keycaps were the thinnest I had ever seen. They are so thin, I actually said out loud, "Wow! These caps are really thin!" They are like egg shells. I was afraid to grasp them too tightly for fear they would break. However, I tested them on a white Alps board, and they worked just fine. There was no detectable difference in sound, but the feel of the PBT was better than the feel of the stock ABS caps.
In contrast, I have had thick dye-sub PBT caps for Cherry mx that had problems with ill-fitting stems and thick walls that interfered with stabilizer wires.