I think, seeing as how it is a spin off, and thus a subsection of Persona, it will obviously take a lot of influence.
Well, Persona actually started as a spin-off of SMT, rather than the other way round. But regardless, to answer the OP, since they've shared a lot of enemies, spells and general battle system through their many entries, the two series are fairly knit together anyways.
The games however are not developed by the same studio and have a different atmosphere to them, and i think rather than hail Persona 5 as their untouched, sucessful masterpiece, they'll try to make an amazing game in their own right, which is the better approach in my opinion.
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