Not sure if anyone posted already.
http://eu.square-enix.com/en/blog/who-hajime-tabata
“Previously I would have said FF-I and FF-VII were my favourite to play but while making Final Fantasy XV, some of the ones I’m referring to the most and the ones I’m drawing the most inspiration from and getting a lot out of are FF-III, FF-IV, FF-V and FF-VI. The more I look at them, the more I think – wow! They’re probably some of the lesser-known Final Fantasy games but I think there’s some really great stuff in them and they’re a really good help for making FF-XV.”