My $.02 or so - This "widespread castration" would force application
developers to jump through the same NAT-traversal hoops all over again,
adding more code-bloat / operational overhead and stifling innovation.
Naturally, once created, this lower-class of internet user would probably
become the "norm" and force a race to the bottom in terms of capabilities
and performance (or perhaps, another "arms race" between the proxy
implementations and the proxy avoidance implementations) ...
rinse-repeat-fail_to_learn, all over again.
That was kind of my point.
PS - could we choose a different term; "cut-rate castration" brings
unpleasant medical-accidents to mind ...
How about "net neuterality."