You also have to consider the proliferation of "Special" targets that have now appeared in HFT. The Traditional targets and their dimensions have evolved over a period and are usually reliable.
With the "Special" targets we have moved away from "Standard" and are using scaled down faceplates, different faceplate designs and shapes and also different kill shapes. These targets have not yet stood the test of time to prove linkages and operation, especially reliability.
These "Specials" also make it difficult to replace like with like, should the target fail.
I think the "Specials" do have their place but we may also have to accept their limitations.