Field level security / permissions.

Azure DevOps - Security - Organize roles per service/section and visibility control

Allow testers with Manage Test Artifacts Permission to be able to delete test artifacts again

Make Service Hook Permissions more flexible

Visualize the rights of a user/group on all different aspects of a Team Project

Team level access

Control who is allowed to use the REST APIs

better permission management (user interface, identity picker)

Separate Test Suite Permissions - I would like to see Modify and Delete as separate permissions in TFS

Ability to link VSTS to Multiple Azure Active Directory instances for Vendor Collaboration