Actually, if you look into this, you’ll discover that the Vatican has been recognizing the valid priesthood of individual Anglican ministers for decades. This was possible because of the involvement of Old Catholics in Anglican ordinations starting in the 1920s (if I recall correctly).
Here’s an example from 1959: http://philorthodox.blogspot.com/2008/10/vatican-recoginition-of-anglican-orders.html
Leo XIII did the right thing - but the circumstances changed years later once Old Catholics got involved. Personally, I think it’s best to just assume all Anglican orders are invalid, but I’m not the Vatican.
That's a harder conclusion to come to after reading Hughes' book on the subject. I've not heard of another exception made, though there may be some.