Agreed, but I think they took a second approach that was also workable: Offer as much guidance and as many tools as possible (.e.g., 2to3, from __future__ impo

Agreed, but I think they took a second approach that was also workable: Offer as much guidance and as many tools as possible (.e.g., 2to3, from __future__ import, etc), and then expect it to take years for the migration to occur. I don't know how possible it was to run both in the same interpretor process; I believe that it wasn't just because of the changes they were contemplating. Lots of people like myself have been following our key libraries, but it's worth noting that, at this point, the migration seems both inevitable and not terribly difficult since 3.3 fixes most of the complaints about .0 and .1, and a lot of struggle to migrate has already been accomplished and offered lessons learned.