Those keys are proprietary regardless of whether or not they have changed. Just because Microsoft may have access to them doesn't mean they can arbitrarily update the phone using them without Verizon's explicit approval. Microsoft does not control any carriers' network. Again, if Microsoft tried to go around Verizon, or any other carrier for that matter, they would get themselves into serious legal trouble.
Now I would think if it isn't directly related to network operations (i.e. camera, audio, Bluetooth, WiFi, etc.) then Microsoft should include it. Anything dealing with the LTE, GSM, or CDMA side could be updated by Verizon; or approved by Verizon and updated by Microsoft. But since many phones have system on a chip architecture, you just can't update one aspect without updating the entire system.