Per issue #1595, the user camera pose can be viewed from the Scene element in the gui. The components can also be set individually for increased precision. I also made sure that the pose field would be expanded when you click on Scene. It's always a pet peeve of mine that the pose elements are not automatically expanded in the gui.
@iche033 also helped me set reduce the size of the increments of the roll/pitch/yaw fields so the scroll wheel is more useful.
The camera_pose field, unlike the other properties currently under scene, is not a field of scene.proto. Therefore, the other fields are published in a message and changing them on one gzclient affects other gzclients, unlike camera_pose.
Since on SDF the camera pose is described inside <world><gui><camera>, what do you think of creating a new field in the World Tree above Scene called GUI and inside it put camera, which expanded has a read-only name == user_camera and an editable pose field?
That makes sense. I used Scene because it was already there and my qt skills are minimal. I'll need some guidance on how to do this.