sender rewriting scheme

Is there a better solution to the .forward problem than sender rewriting?

Any kind of designated sender scheme will, in the worst case, break
every .forward in existence.

In the worst case that means we need to patch every MTA in the world to
do sender rewriting for .forwarding.

This is huge.  They are innocent bystanders caught in the crossfire of
our consent system.

Is there a better way?