3D View: Rotation around / zoom on mouse cursor
Similar to Cinema 4D, or with a slightly option change in Maya, rotating/tumbling around objects can be done around a point of interest, in this case the mouse cursor location.
It is frustrating to try to rotate around / zoom from a point on an object in 3D space when the rotation origin is some arbitrary point in the scene. I'm guessing its 0,0,0 for Designer's 3D View all the time. Having that point of rotation / zoom be exactly where the mouse cursor is when the user 'alt+left/right clicks' clicks allows the user to more reliably navigate their object, especially if it's an imported mesh.
Worst case scenario for lack of this feature is an imported mesh like a pencil which is very long proportionally on its Y axis to its X. Trying to get a good angle of view on the extremes of the mesh in Y axis which are far from the 3d origin proves navigation for this scenario to be unnecessarily difficult. Rotation / scaling around mouse point would solve this.
Thanks for reading :)