Their ideology has not changed, in my opinion. I highly doubt that anyone who has followed the propaganda of the extremeist wing of the Islamic movement before 9/11 (i.e., very, very few Americans) would say that the message or ideology has changed. They want legitimate governments (i.e., NOT Saudi Arabia) in Muslim coutries ruled by Islamic law. They want the U.S. to cease interfering in these interests, specifically as it regards the Israeli-Palestinian conflict.
I'd say the tone of bin Laden's messages has been far more temperate lately, but the overal ideology remains the same.
By the way, that Churchill quote is idiotic political rhetoric. Crocodiles don't eat unless they're hungry. "Terrorists" don't attack unless you provoke them. That's the truth.