The Pilots log or some other representation of the planned route should be editable.

Eg. I cut corners and don't have to follow 3 spurious waypoints anymore. One should be able to delete these points without having to zoom out, drag one over another and than zoom in back. This may be error-prone in turbulence

This is what the Direct To feature is for. The documentation should cover it but in short, use Direct To to make a shortcut to a waypoint further along in your route, and SkyDemon will eliminate the intermediate waypoints just as you intend. More buttons facilitating a reorganisation of the Pilot Log are not the best answer to the root problem, which is to quickly effect an ATC instruction (or otherwise) to immediately proceed to a waypoint further along your route.