The I2C rework is now merged into RIOT’s master branch, then I am really happy to announce you the end of the I2C embargo ! Don’t hesitate to ping pending PRs that were blocked by this embargo so maintainers can have a look at it.
This rework will not be present in the 2018.07 release as we lack of time to get things merged, but you can use the master branch if you want to use it.
We also create a wiki page  to summarize the changes introduced by this rework. We will keep working to improve this documentation.
Of course, we cannot guarantee that the new I2C interface is completely bug-free. So if you encounter any errors, weird behaviour or if you have any questions, don’t hesitate to send an email to the mailing list or create an issue on Github. We will continue to improve our work.
Finally, I would like to deeply thanks every people involved in this huge rework, thank you for your time and your hard will. I’m really proud of what we have done here ! You guys are amazing
Keep RIOTing !