I understand what you're saying, but I think you're confused about the nature of the complaint.
The Century firing pin is similar to the IMI spring loaded. The firing pin as a whole is not fatter. It has a T area towards the rear of fp w/ a spring between the T and conclusion of where Century stopped milling. Purpose is to avoid chance of slamfire on domestic .223 loads with soft primers vs mil spec hard primers...
HOWEVER, my point was that people aren't saying the design is bad. The manufacture of the Century firing pin, and it breaking in extremely short order due to crappy metal (metallurgy) is the issue. There may be issues w/ how they machined the bolt to fit the FP, but it's secondary to the main issue of firing pins breaking...