I wish there was a data audit log for your account. I'd like to be able to check which companies accessed what part of my data, when, and for what purpose. If I noticed something I didn't like, I could revoke permissions. If I noticed something that seemed very shady, e.g. Spotify editing my private messages, I could start an escalation.

This seems like a good way to move the burden of auditing partners onto the users for Facebook to me. Make application fill in information about why they call specific operations, make those operations and reasons available in an audit log that any user can review.