I think it's the fact that so little of it has been shown. I mean, sure, the persona games aren't know for their wall to wall marketing campaigns but as someone who has finished P3 and P4, I have 0 idea what is going on with P5. I was on GB when they posted the E3 trailer and it seemed like a whole lot of the same footage we had already seen, just packaged differently.
I know that it's about slaves and the motif is red this time and that there are shadows? I know more about the Persona 3 & 4 spinoff games before they came out than this, a legit Persona game release.
Nothing seems to point to a 2015 release regardless of the amount of times they say it'll happen. Theyre not being coy about their other Persona releases but P5 sure seems like it's not getting out there that much