Both Calhoun and Tennant were part of the study group that developed the new policy. The earlier policy dates back to 1987--ancient history in Web years.
Richard Wallis does a great job in this interview. He pulls together questions from emails he received. Many of the questions posed in the library blogoshpere on this policy change are addressed.
If you work at an OCLC member library (or you're considering membership) you will want to listen to this podcast.
My take: Having asked for and gotten permission to use the new WorldCat Search API to extract and overlay WorldCat records for one of our digital library project at work, I am sympathetic to OCLC's goal of wanting to enable their members to use WorldCat in new and innovative ways.
Also, I do think that OCLC has certain rights over the database with all the transformation that goes on (at OCLC) with the records created and submitted by member libraries. OCLC doesn't just stockpile our records. However, the issues are complex. I'm also very sympathetic to an open data paradigm. I'm going to keep reading and thinking about the pros and cons. One thing for sure: this is a very significant issue for all OCLC member libraries to contemplate as we all move toward using the Web to communicate with our users.