the internal debates of others should not matter less. As I understand what is being said they will still be able to import from WMF projects;
For a limited time - until some bit of cc-sa material is incorporated into a given article.
They'll still be able to incorporate any of the GFDL or dual licensed material, which is all that really matters since if they want to copy the *entire* article and not some specific part, there's nothing from their site to relicense anyway.
I'm worried about small sites that want intercompatibility with WMF
projects (which are the gorilla in the room), and larger ones whose communities expect this to be a standing option. In terms of raw content, the fraction of new material that is imported from sites that aren't already considering switching is small. But we have a certain obligation to act as stewards for the free sharing of knowledge, in a networked community that we have helped to build, including thousands of groups who we don't directly see on Wikipedia but who have made choices based on ours in the past.
The WMF should have thought about that before making the switch, though. Instead the official line was that this switch was a panacea, and any suggestion that there were legal problems surrounding it which acted against the free sharing of knowledge was dismissed as FUD. Short of a miracle, it's too late to fix it, though.