This change will undoubtedly make development easier for Google’s team, but it could limit how much we know about Android before new versions are official. Sometimes, the tidbits that appear in AOSP can point to upcoming devices, feature removals, or changes to app support. We may not get those insights anymore, and consequently, there won’t be as many opportunities for devs and users to challenge Google before it rolls out an unpopular change.

Source: Google makes Android development private, will continue open source releases

This is worrying. We need more competition.