One of the experiments Mullenweg proposed is to remove the manual review process and rely more on user feedback

Deep in the WP Tavern archives are conversations where a large number of people suggested this originally. There was quite a deep divide between those of us who felt this was the only way forward due to us feeling it was not viable to manually review every theme without creating bottlenecks, and those who felt that the way forward was to get more people involved with the review process until it was running smoothly.