It has to be a separate mode, there's no way there were gonna through with that. If it was the default mode you would only see very few characters rotating.
Vanilla Sagat, Akuma, Ryu, Rufus, Seth, Viper
Super Cammy, Bison, Adon, Chun, Abel
AE Yun, Fei, Yang, Makoto
In a sense almost everyone...