If you are adopting this stance, there's no point in answering if you can't see the possible ramifications.
What possible ramifications? I would like to be informed, but here's how I see it:
Out of the currently available systems (let's limit that to PC, Wii U, PS3, 360, Vita, 3DS), Vita is the second weakest by a decent margin. Just a fact. Then, out of those same systems, Vita has the second smallest userbase by a huge margin.
So, given these facts, what reasons are there to cheer for a Vita exclusive? Obviously not so Persona 5 can be the best it can be, or else we would want it exclusive to the most powerful console, certainly not held back by the second weakest. Not so it can reach the largest audience possible or else we would want it on every console. Failing that, we'd want it to be on consoles with the largest potential audience.
So, again, why want it Vita exclusive with this info. If you only own a Vita, you might honestly wish to see Persona 5 limited by the Vita's power so it can be multiplat on your console. But no reason for exclusivity.
So why exclusive? As far as I can tell, the only reason would be Vita fanaticism. Wanting the Vita to "get the recognition it deserves" and Persona 5 being a perceived great way for that to happen.
Not trying to put on a fanboy show here, I own all these systems save the 360. I am just baffled to see, on one hand, a dismissal of the 3DS because we don't want the game "held back," while at the same time so much open encouragement for a Vita version.