Following a discussion on the Commons Village pump, I think the contents of MediaWiki:Wm-license-cc-conditions-attribution-text should be updated to more accurately reflect the requirements of Creative Commons licences. Lacking any good reason to do otherwise, I'd suggest using Creative Commons' own wording (seems to be the same on all Commons deeds):
You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
This would supersede T75387, which just asked for addition of the requirement to link to the licence.
Creative Commons states that their license deeds are in the public domain, so there should be no problem with stealing their wording.