While that density thing works, there should be some easier tool-sets or hotkeys to quickly select and erase either all foliage types or per single foliage type. Typical example: Having 10 different foliage types in a forest and just want to quick-erase some path or area. Maybe I am stupid but never found a quick way to use that.
Alongside this, a smoothing terrain brush hotkey would be cool that works anywhere for quick tweaks…even in foliage mode? Or some quick landscape mode-changer with mouse wheel for quicker access. The little things that makes the whole terrain creation / foliage placement a little more convenient and much faster.