It seems that the "hardened system" approach you discuss prefers
everything to be wired down and as little as possible to be
configurable at run-time.

However, the general trend of development is for increased runtime
configurability and flexibility (reflecting, among other things, the
larger variety and hot-swap ability of modern hardware and
applications).

It's not obvious to me that it makes sense, or will continue to make
sense, to try to accomodate both of these ideals in the same system.

I'm not really sure what conclusion to draw from this, but I think the
general issue needs discussing. The continued proliferation of "make
more flexible, but add an option somewhere to rigidize" changes is
very unwieldly in implementation, documentation, and testing.

        - Nathan