I think there's one factor going against SMT x FE that wasn't applicable to XCX: how many people in Japan that own a Wii U also own a PS3 or a PS4? This is a number that would be helpful if anyone can point to a survey or something.
This is important because, in Japan, SMT x FE is slated to come out at approximately the same time as Persona 5. It is safe to assume that there is a great deal of crossover between fans of both series. Also, since both games are 'hardcore,' it's arguable that the fans of the series would be more likely to have multiple consoles. Consequently, it is arguable that the sales of Persona 5 will cannibalize the sales of SMT x FE, something that XCX didn't have to face.
Of course, if Atlus has any control in determining when the games will release, they will actively try to put the games as far away from each other to maximize sales for themselves. It is likely that Nintendo has more direct and active control over the production of SMT x FE than Sony does over Persona 5 (which is probably just limited to the PS4 port, marketing, and/or localization, if anything), so I'm assuming that if there's any push to release either game at any point, it's by Nintendo and only for SMT x FE.
