Kwan Ting Chan writes:

There is either a legal need for WP to provide an opt-out if/when it relicense under a later (major revision) version of GFDL, or there isn't.

The Law of the Excluded Middle is less helpful in applying the Law of Copyright than you might imagine. The latter, like all human legal systems, is far more probabilistic and far less binary.

True. But in practise, the foundation will based on the advice given to it by its counsel, decide that there either is a need or isn't.

The Foundation's actions will be based on many things most likely, and only one of the factors will be my advice, or the advice of other counsel we consult.

--Mike