It really didn't take long for libraries to catch up, we already released a Package Set compatible with 0.13, two days after the release. That's a set of the most used ~200 libraries in the ecosystem.
Yeah I agree with @ff_57 here - the "breaking changes" really aren't a big deal, and don't effect many libraries. With the existing tool chain you will know immediately if a library has any of these incompatibilities, and if it does, the fix is likely some white space issue, which is trivial to fix.