Currently you can initialize user metadata during creation by passing an object of key/values in the request body. However, if you want to update the metadata you have to hit a different endpoint.
I would like to request the ability to update a user including an object of metadata with a single request at the following endpoint.
Opposed to making 2 concurrent requests. In this case I would expect the to upsert, or fully replace existing values.
I believe channels operate in a similar fashion.