As I said elsewhere in the article, the goal was to NOT change the current workflow for patch approval. Keep in mind that the PostgreSQL project has a smaller ecosystem than Linux; there's only 26 committers and around 100 active major contributors, so the centralization is not considered a problem.
More importantly, several committers did not even try Git until the migration happened. Before we could even consider changing workflows, all contributors will need to be comfortable with Git. That's at least 6 months off, which really means for the 9.2 development cycle *at the soonest*.
The changes to the Commitfests don't need to be dramatic; in a lot of ways, linking to a git snapshot would be much easier than the current e-mail-and-link-to-archive method. However, when you have people who have 14 years of experience reviewing context-diff patches for the project, they're not going to adjust quickly to another method. And there's no reason to make them adjust quickly, either.