@ Opossum the Awesome
Here is everybody's reaction to the first line of your post. (don't lie and say you didn't do this)
Seriously, Rocket Grunts, possibly with various Pokémon (various normal, poison, rock, and ground type Pokémon) would be KILLER!!!
Also, I thought of an enemy I would like to see: Metal Gears. I don't care if its' Gekko, Ray, or Rex's (whether as common enemies or bosses), I want Metal Gears to battle, possibly with a chase level, the ability to sneak around and get kills, loads of explosives and weapons (by each Metal Gear), and loads of Metal Gear references.
What about your eyes. Your right eye and your left eye, staring at you. Oh god, I've just made myself paranoid by typing this.
Smash Bros is about punching and jumping, not starring.
Still, the strongest part of the human body that could be used would be a certain part of the male and female body (because of the ability to use long-range projectiles!).