I have a theory that the damage system became more complicated, as Mario also did 2 damages in one jump to a Goomba. During a Multibounce attack. But apparently the truth is that he's wearing the Super Boots there. So I don't know.
Maybe spikes, flames, and other items the enemies possess do more damage than they did in the last Paper Marios. Or, the Boot System could decrease the number of damage you take from things like that as you gain more powerful boots..
You people are rocks. You don't live under rocks, you're simply the rock. - Knifegash