One of our users has misunderstood navigation help and tried to use multi-touch gestures on touchpad to navigate around. See http://youtu.be/OEW6wlvWliU.
He said the same works reasonably in Google Earth plugin.
Do you think this can/should be improved in Cesium?
We would definitely love to support it. The main problem here is that the state of input handling on the web is very fragmented and it’s very difficult to handle the variety of input devices available. The solution is the PointerEvents, but there are problems with standardization there that I won’t go into. While the issue is now misnamed, check out this link for some other thoughts: https://github.com/AnalyticalGraphicsInc/cesium/issues/2631
I would also recommend taking a look at hammer.js, it’s a third party library that is being headed and developed up by some highly knowledgable people in the mobile UI community.