Idea / Pre-RFC: Null-free pointer and Zeroable reference

H4n_uL:

consequences of changing it, or an example of code whose soundness depends on this axiom beyond NonNull<T> - appears to have been presented in this thread.

So aside from an integral part of the language, which you're explicitly disregarding for unclear reasons.

H4n_uL:

so this point is settled.

That's not at all how the process works. Addressing the top-level post itself in its current state, it is still not clear why you necessitate a language change here. Everything you propose can be accomplished in a third-party library. You can't simply declare something to be true while closing your eyes and plugging your ears. Issues have been raised; you are the one that needs to address them.