Exchange Online Admin API Support
There is an adequate amount of client side Rest APIs for outlook, but nothing truly available on the admin side. Allowing API calls to create Online Rules and Connectors for example would (hopefully) be less error prone than manually invoking Powershell sessions, especially if rules and connectors need to be created en masse.
The team is currently planning and reviewing the requirements of request. We will provide more updates here once a timeline is confirmed.
I would also like to have the possibility to convert between shared and personal mailboxes and delegate permissions on the mailboxes using the microsoft graph api
As best I can tell, Office 365 doesn't have a way to manage users / mailboxes directly via some kind of web service.
This is extremely problematic when trying to integrate the system into existing account management procedures, which might well not be running on Windows.