Do some type of integration with Azure AD so you do not have to worry about the security or any of that? Plus clients will be familiar with it and could use existing users in their infrastructure.
That's a good suggestion. But in reality we'd have to support both Azure AD and our own storage for users who are not using Azure AD. And possibly even on-premise version, which is additional complication.
It's beginning to look clear why it's an idea from few years ago but still not implemented.