As a Googler (who does not work on Hangsout) my own personal opinion is that I fully agree with the EFF here:

"In public explanations of its dropping XMPP support, Google has said that it was a difficult decision necessitated by new technical demands. But even if this new protocol responds to different technical requirements, that shouldn't prevent the company from making it public and interoperable. Releasing the specifications for Google Hangouts would be a good first step. Releasing free/open source clients and servers should follow. It's clear that some of Hangouts' video features have been implemented in some very Google-specific ways. But that's no excuse for leading us toward a world where the only practical choices are proprietary chat clients and protocols."

I hope the specs at some point are opened. The Hangouts team probably has good reason at the moment to strictly focus on a core set of functionality and get it working with good UX on all the platforms. People are complaining that stuff like voice calling, and some Talk features are missing, but it's probably due to focus on shipping something that works good first. It's inevitable people will reverse engineer the client, as was done with MSN, Y! Messenger, and AOL. In the late 90s, early 2000s, I remember using reverse engineered Java libraries that could talk to these services.

Google Wave was done in the opposite way, as was Open Social. They came with specs, but they did not focus on core user experience in the beginning. It's hard to win with open specs without getting consumer traction.

It's such a surreal concept to me that having to be picked up by emergency services will cost you money. I feel so incredibly lucky to live in a country where healthcare is free.