Terrain manipulation after step 3

Pix4d mapper desperately need a way to manipulate and correct terrain. The automatic pointcloud classification is only 80% right which is still completely useless as the terrain will be incorrect and riddled with artifacts regardless.

Of course a better terrain algorithm would be awesome, in the meantime we need a way to manipulate the terrain model in the software before export.
A simple flatten/smooth/lift/depress and size selector tool would do wonders.

I have hopes but experience with pixd4 community requests leave me with little faith however.