Extend Cesium to support non-mouse controllers
It can be difficult to navigate a 3D environment using a standard mouse.
There are other solutions available like the "space mouse", leap motion, or game controller.
The Cesium API includes all the needed moments required for these alternative controllers: https://cesium.com/docs/cesiumjs-ref-doc/Camera.html.
In addition a cesium plugin has already be developed for leap motion: https://github.com/Aviture/cesium-leap.