As I started to use a variety of 3D viewers besides FME DataInspector I came across a very useful feature.
It is a constrained orbit mode tool which "restricts" orbiting in a way that it always keeps the ground horizontal. That way you avoid tilting your view in ways as if you are doing 3D aerobatics and get lost in the strangest rotations.
Especially in dealing with 3D geographic and building data, which is the vast majority in FME context I think, this is what you want to do most of the time.
So my suggestion is to add such a "Constrained Orbit Tool" to FME DataInspector.