I don't think your proposal is "wrong", I just think that it can't solve the
problem.
My proposal is a mixture of
1. your proposal (writing as many userscript replacements as possible)
2. stallman's proposal (trying to convince as many server owners to release
their code as free javascript; i know that you're concerned about the scripts
being executed without the users consent, but this could be solved with an
addon which asks the user for confirmation to run script xy in version wz; he
could agree to run the free scripts of the most visited websites with
somekind of whitelist)
3. live without javascript if point 1 and 2 didn't work out, or make somekind
of workaround (element inspector)
4. make a compromise for the rest (just like we do with non-free bios)
Web-technology evolves quickly and chances might be decent that a new
technology will make javascript disappear... like it happens with flash to
some extent at the moment.
I have to say that I gave it some thought and that i'm not so pessimistic
about your proposal anymore. I mean there exist already a lot of userscripts
and they modify a huge bunch of websites... unfortunately not for freedom's
sake.
Still I think that we need to combine all the means we have right now and
then we need a bit of luck...
