There is an important difference between the Creative Commons licenses and several other leading “Free” licenses.
The GPL was written by Richard Stallman in response to non-disclosure of code harming programmers ability to work as they had before. He wrote the GPL to ensure that programmers could continue to program.
The OGL was written by Ryan Dancey in response to the financial collapse of the games company TSR threatening gamers ability to play and write role-playing games, specifically Dungeons and Dragons. He wrote the OGL to ensure that gamers and game authors could continue to work with D&D.
The Creative Commons licenses were written by Larry Lessig in respone to overly strong copyright threatening individuals ability to exercise their fair use rights and gain access to works in the public domain. He wrote the CC licenses to counteract this.
In each of these cases there was a “printer driver moment”; for Stallman not being able to get the code to a laser printer driver (hence the name), for Dancey realising that the collapse of TSR could lock D&D away for ever, and for Lessig the Eric Eldred case where “orphan works” would be lost to unknown rightsholders.
So the GPL was written by a programmer so he could continue to program in the way he was used to. And the OGL was written by a gamer and games author so he could continue playing and writing games as he was used to. But the CC licenses were not written by and for their subject. Eldred did not write the licenses, Lessig did.
This difference explains the character of the CC licenses and their presentation. And some of their strengths. And, if you believe the CC licenses are flawed, some of their flaws. Despite being an author, Lessig is primarily a lawyer and does not have to “eat his own dog food” using his licenses in his day job. Any weaknesses in the CC licenses will not affect Lessig’s ability to practice law. But the GPL or the OGL could bite their authors hard if they have any flaws.
This is not to say that the CC licenses are bad or morally defective. In their own way they are excellent. And they are head and shoulders above half-hearted licenses like Sun’s execrable CDDL. But being written for an audience rather than written by their subject has affected their genetic makeup, and this is a factor that is worth considering when discussing them.