Wow, that is a juicy rumour. At least Namco-Bandai working on multiple titles is a great thing. Smash 4 might be a great idea for the system (it would be horribly difficult to surpass the Smash4 roster), but I can a backlash and people complaining about the risk of not being a Smash5.
I just want a Digimon game on the NX. Do that, Namco-Bandai, and I'll be happy.