The point isn’t the pope’s works or accomplishments. It is whether God actually “told” him to do it. How was it done? Did he hear an “inner voice”? Did angels appear from heaven to deliver the message? And then there is the response by other Christians. Why do Christians believe some people see visions and accept their from God while rejecting others? Why are we willing to accept the pope’s statement on face value and not others? Is it because of our prejudice?
I have nothing against Joseph Ratzinger just like I have nothing against Pat Robinson. My point is that Christians cannot rely upon the testimony of some that what they’ve encounter was God talking to them and reject others. We can only say “Hmmmm....that’s interesting.” or “OKay.....” but that is about where we have to leave it. In the end we have to look at the scriptures.
Personally, I think Ratzinger made the right and courageous decision. This sounds more like regrets and excuses. But that’s understandable. If the Pope had said, “I’ve prayed about it and felt God was leading me to resign for the betterment of the Church.”, then that’s fine. Ratzinger would never and could not have resigned if it was not for the will of God-whether he was told by an angel or not.
As to the inner certainty he evidently felt, two questions arise: do you believe Ratzinger, and do you believe the anonymous source? In the case of Ratzginer: yes, sure I do. And the anonymous source? Anonymous sources are by definition impossible to verify: I mentally put a big red parenthesis around anthing alleged by a person who won't give their name, with a footnote that says, "Pending further verification."
I suspect we all do more or less the same thing. Or should, anyhow.
The Church smackdab refuses to promote unverified mystical phenmomena. The most recent was a series of alleged visions at a town in what is now Croatia, starting over 30 years ago. All the bishops of the Diocese of Mostar have ruled the claims groundless, but public interest has persisted, and he place continues to draw millions of pilgrims. The Bishop has nevertheless prohibited "official" pilgrimages, so thse excusions can't be sponsored by parishes or diocese. They obviously can't prohibit individuals and private groups from traveling there: anybody can travel anywhere they want.
However, the priest who, from the first, was the main publicizer of the (ongoing) visionaries, was laicized and ordered not to have anything to do with it anymore. This, despite the fact that, for over 30 years, millions of people -- and by no means all of them Catholic --- have flocked to this village, Medjugorje (Link).
Which effectively illustrates the non-committal or outright skeptical point of view the official Church takes, unless there's a stack of verifiable evidence.