I've thought for a while that P4D could be pushed into 2015, so P5 can come out here simultaneously or within three months of it's JP release. Obviously it's a higher priority for a multitude of reasons.
Most people couldn't see it for SMTIV, but the wait was so short, it basically happened.
Persona 5 will presumably be far different than SMT IV, though. For one, I wouldn't really call a two month interval simultaneous.
But SMT IV has WAY less text and VA than Persona 5 will have. I'd say a fairer comparison would be Persona 4 Arena in terms of text and VA—which they also said was their biggest localization project yet when it had come out—but even that'd be a weird exception because it's a fighting game + visual novel.
Pushing P4D and PQ aside, I think, would be the "safest" games to push aside if they were to prioritize Persona 5 somehow, since they'd probably want to get P4U2 out close to the Japan launch since it's a competitive fighting game, but who knows if that'd actually be a smart decision or if that's even feasible.