If I'm not wrong, you get damage for every step of movement, that hits enviromental ground. The distance between those steps most likely depends on your movement speed. Dashing counts as even faster movement, therefore there are even less steps taken. Steps are the dots shown as line of movement I would say.
Splattered ground effects are often hard to identify, where now ground effects would happen and where not.
Showing damage to expect is difficult, you don't path the way before executing and the damage can vary from step to step because it is not fixed.
As long there is enough magical armor, I hardly card about the ground damage honestly.
