Well, the problem in this case is that the character superiority is based on the only thing the gametype is judged on. In the other gametypes the thok is powerful, but it's not the only thing that's important to the mode but it's okay. Since race is based entirely on speed, the only thing that matters is which ability lets you get through the stage the fastest. Most of the time that's going to be Sonic, but on occasion it'll be another character because flight or climbing lets you skip vast portions of the stage.