[...] You can't reuse an article safely without attaching the entire GFDL. [...] That applies to all copyright licenses, the GPL included.
It doesn't apply to CC-by-sa.
Indeed it does. It is the whole point of a license, you cannot know the license terms if you cannot see the license.
| * For any reuse or distribution, you must make clear to | others the license terms of this work. The best way to | do this is with a link to this web page.
Er, no. A link to the licence web page is not including a copy of the whole licence. That's the point of CC-by-sa being considered a more sensible idea for Wikipedia than the present GFDL, which is technically "free" but is monstrously ill-suited to it.
And you can do exactly the same thing with a GFDL work. For example,
| A copy of the license is can be found at http://www.gnu.org/licenses/gfdl.txt
instead of:
| A copy of the license is included in the section entitled ``GNU Free | Documentation License.''
Attaching the entire GFDL 1.2 text is not meaningfully "free" for photos or single-page texts. And how do you reasonably implement it for a motion picture.
This would fall under fair use. But I fail to see what a motion picture has to do with this, if you use a copyrighted work, you have to note that, and its license.
No, you're answering something other than what I wrote. Wikimedia Commons includes images and motion pictures under the GFDL. The originals don't include the entire licence in the movie itself; how is this to be meaningfully reused? The answer in practice is "it isn't" - the licence fails in practice at reusability.
See above.