Fr Hans Kung's open letter to the Bishops of the world is interesting as a phenomenon of dialogue - or of non-dialogue - in the Church. Blogs that are faithful to the Church pretty much ignored it. Dissenting sources lauded it, and gave it good coverage. I had difficulty understanding why main stream media outlets were giving it coverage, as Fr Kung is really quite marginal to the life of the Catholic Church these days, and has been so for many years.
If you read Fr Kung's open letter, it seems very plausible. It is another example of saying something confidently in public and thereby having it believed, regardless of whether or not it is really credit worthy.
The open letter appeared on 18th April 2010. On 21st April, the website of the American edition of the journal Communio posted a link to an archive article by Hans Urs von Balthasar On the Withdrawal of Hans Kung's Authorisation to Teach. This does, of course, put the whole position of Fr Kung into its proper context - essentially that of dissent from what the Catholic Church believes. And one can then see the open letter rather more for what it is.