Don't get me wrong I'm super hyped for the Cross Tag Battle fighting game but for people like me with no friends it would likely be something I wouldn't play much. That was an issue I had with RWBY: Grim Eclipse, as well as a couple other problems with the game but I won't get into it.
Basically I want to see a RWBY game that's single player/story driven focused. Since the story of RWBY is just as important as the awesome fight scenes. And it would be a great way to expand the lore of the RWBY-verse. Whether or not the game should be a 2D or 3D game is up to debate. Personally I want to see a 2D one.
Though I'm pretty sure the game production side of rooster teeth were working on something else at the moment, can't remember the name right now though.