thats not to say that there are no wads worthy of the same kind of situation. not every wad is overpowered. you could just make it so that a character can only go super if they have stats within a certain range.
The Disco Room's reward is an emerald token. Furthermore, the black emerald is useless and the Disco Room isn't difficult to clear.The Black Emrald should be the reward of The Disco Room.
Should Super Forms be in Single Player/Coop?
No. They remove the uniqueness of Sonic. Even if they are wads like SonicCE or ShadowRE. And allowing them on characters within a certain range of stats would probably be too hard to do, and not worth the effort.
FAIL
I don't like your opinion, Sonic is not the only one with super forms, there are characters in the new generation that are able to turn super:
Blaze = Burning Blaze (if it's not a super form, then it's a burning form)
Silver = Super Silver
Shadow = Super Shadow (it never was Hyper Shadow >.>)