Leaving the OGL behind isn't an option.
Really, what Phil is doing is doing cost-benefit analysis to releasing products as 100% Open Content.
There are advantages to this. Fans like it. It increases the likelihood that other publishers can make use of his OGC and drive customers back to Phil.
There are disadvantages to this. Some fans might decide-- legally, ethically, morally, who cares?-- to distribute Phil's work free of charge.
And all Phil's saying (if I can put more words in his mouth) is that the recent emergence of an OGC Wiki with a respected industry figure putting momentum behind it means that he has to reassess the risks.
It will mean one of two things:
1) Phil resorts to "crippled" OGC designations that are designed to obfuscate the OGC and elevate the threat of legal action if the user runs afoul of the license; or,
2) Phil quits the d20 publishing business and gets a 'real' job (and within months, gamers are complaining that there are no good designers in the RPG industry anymore).