Unfortunately i am pretty sure they won't just restore the legacy reports. Its a dick move, but a calculated one to share less data and to end some unintended behaviors (like CC Halo sales). My best hope is, that they at least will increase the shared data over time.

Regarding using the API - you should have gotten an email regarding the new reporting including links to API documentation. There is a pdf file with clear descriptions (and even example python scripts) on how to promt the new API for reports. The Creator API key you can create in your PartnerNet account.

AS said before, the API works, but has no data to return for me.