Of course he rules! Scorpion is one of the most Iconic Video Game characters in history. When he wasn't in Mortal Kombat 3, Everyone raged that Scorpion wasn't in it. You can't have a Mortal Kombat game without Scorpion! That's like having a Street Fighter game without Ryu!
Another reason why Scorpion rules is how well of a character he is and the voice he has. Nothing is more intimidating than having the Ninja from Hell coming out of hellfire and threatening you. If you ask me, Scorpion is probably more threatening than Shao Khun!