I think it would be great if Unity allowed us to integrate Google Play into the games for In-App-Purchases, Achievements, Leaderboards, Cloud Save, etc, etc.
I know there are some plugins (from asset store) out there, but this integration sometimes is very important to leave it up to a third party.
Sometimes these assets manage Android permissions wrong or get un-updated.
And maybe a similar solution with Facebook integration, and other social networks.