I have to wonder if Pope John Paul II might have been more considerate of Küng's request to meet if Küng weren't so vehement in his polemics. Openly ridiculing the Holy Father as a third-rate theologian with "a very thin theological foundation -- not to mention a lack of modern exegesis, the history of dogmas and the church" and accusing him of betraying Vatican II" by "rigorous moral encyclicals [and] traditionalist-imperialist world catechism" (as he did in his biography ) doesn't exactly cultivate an amicable relationship. If anything, this week's conciliatory meeting is a testament to Pope Benedict's patience, forgiveness and goodwill.
I agree with Chris' assessment, and I would add that this gesture by His Holiness will perhaps confirm the statements made by some, early in this pontificate, that Benedict XVI would be a "surprise" to some, but I think he may surprise others as well when they find that he sticks to his orthodox treatment of dissident theologians like Küng. I'm all for love and forgiveness and all that, but there's no reason why theologians should not be held to the same standards as the rest of us--namely, the fact that a necessary condition on forgiveness is repentance.
Who knows what the future will bring in cases like Küng et al. One hopes it will be a future of well-deserved forgiveness.