Just as the methods of determining the inputs can change as the state of the art changes, the formulas that translate the inputs into capital requirements can be modified as well by the regulators. Basel II can improve as knowledge improves.
The rules surrounding Pillar I are clearly more complicated than I have just described, and the volume of comment letters and the number of pages that have been and will be published for comment will attest to that. One reason for that complexity is that the large, complex banking organizations, to which the rules are addressed are, in a word, complex.