This actually was one of the strangest documents to come out of VatII. While the principle is not particularly remarkable - even virtuous pagans born before Christ were deemed to have been seekers after the true God (which one could tell from their virtuous lives)- never before was so much praise heaped on the religions themselves. And it does indeed seem in that fatal footnote that Catholics are being told that everything's groovy, I'm OK, you're OK, and what is Truth, after all?
I think he does make an interesting point, which is that we need to examine whether all of the bad things that came out of VatII were a result of its "misinterpretation" or whether some of them were actually supported by the documents themselves.
I think in general most of the documents are harmless, that is, vague and wordy and open to misinterpretation but not fundamentally wrong. However, it could be that it's time to review some of them.
Vatican II has made chances of reunification with Eastern Orthodoxy less likely, not more.
It would be a cold day in hell before the Eastern Orthodox hierarchs would accept Vatican II.