Okay, I think part of the confusion is my fault in insisting that this is fan fiction (because it is), but 'Fanon' and 'Fan Game' are apparently specific terminologies related to this kind of thing. Whereas here, people associate a 'fan game' with someone programming something you can play or using Mugen.

He's making a wiki page for this game as if it actually existed, but it does not and it will not. It's basically design brainstorming for a game that will not be made. Essentially fan fiction.

So he's asking for things that will make the writing on the wiki page better, which is why I suggested that the Writing Corner would be a better fit. Since us gamers would think he wanted to make a playable game.