Ability to prevent subscription association to Azure AD tenant
In terms of Azure governance many customers want to control or rather disable the ability to associate pay-as-you-go subscriptions to their Azure AD tenant, quite similar to controlling who can register applications to the tenant. This is especially evident in an Enterprise Enrollment scenario where consumption is driven by a monetary per-commitment. Often customers aren't even (made) aware of this "loop-hole".
Hey-ho, this would be a great feature. I had to take over and squash two ad-hoc subscriptions just today.