An option to add "geometry lock points" in the geometries with higher priority than the usual rules would be really useful to make the geometry behave as you wish.

As an example it could be the center point of a radius so that the radius keeps it center point and only changes its length when the tangential elements are moved. Two lock points on a line would make it keep its direction and so on...

If this would be possible I think that this could solve the problem that the rules that was applied when the geometry was created not always are good when the geometry needs to be changed. It would also make it possible to repair a geometry that has "cleaned" by the geometry connector.