WotC OGL FAQ wrote: Q: Can't Wizards of the Coast change the License in a way that I wouldn't like?
A: Yes, it could. However, the License already defines what will happen to content that has been previously distributed using an earlier version, in Section 9. As a result, even if Wizards made a change you disagreed with, you could continue to use an earlier, acceptable version at your option. In other words, there's no reason for Wizards to ever make a change that the community of people using the Open Gaming License would object to, because the community would just ignore the change anyway.