YAGNI is one of the easiest to misunderstood ideas behind eXtreme Programming. That's why I think it's a good thing it stays under active discussion. Often people understand it too literally which can create issues. That's why people talking about "PAGNI" (probably are gonna need it) are right. After all, people who also conceptualized YAGNI wrote back then: "This doesn't mean you should avoid building flexibility into your code".