Brianna Laugher wrote: [...]
That way, CC-BY-SA is strong copyleft as default (and that's surely the best thing for the growth of the commons -- all of them), and people who want to extend "weak copyleft" still can. And we don't get confusion caused be an extra official (CC) license.
For the good of the commons we need the default to be strong copyleft, no?
The only problem with that is: we we have "strong" copyleft CC-BY-SA, and follow it to the letter, CC-BY-SA image can not be used in GFDL articles. All pages on Wikipedia that use CC-BY-SA images would have to be relicense with the consent of all contributors. So, such a strengthening would be very harmful, unless combined with a GFDL compatibility clause.
-- Daniel