XVI is not a total shift in tone from what FF used to be, it's a continuation of a shift towards a more mature tone and more sophisticated narrative that was occurring in the series with XII (and Tactics before it) but that Square Enix brass under Wada aborted to double down on the countervailing melodramatic adolescent tone embodied in games like VIII and X (and especially KH and X-2).
Under Sakaguchi, FF's stories became progressively darker and more mature from IV to VI to VII. He then returned to a sort of Dragon Quest-style storybook tone with IX, but that was explicitly a throwback game that was never intended to be the direction for the series in the future. Sakaguchi's chosen protégé was Yasumi Matsuno, whose games are all very dark, mature, medieval political thrillers (Tactics Ogre, Final Fantasy Tactics, Vagrant Story, parts of XII). That's the direction Sakaguchi wanted for the series, because he realized that as your audience matures the sorts of narratives they'll be interested in will have to mature along with them.
The other tendency within FF, and the one that Wada favored, was the idea that the series should just focus on an audience of teenagers and arrested development cases forever. The idea that there are enough mentally or emotionally stunted adults out there who'll just eat this slop up forever so just double and triple down on them and you never need to mature or cater to a wider audience.
Well guess what, that was a terrible idea that's done possibly irreparable damage to the franchise. The biggest RPG of the 2010s was The Witcher 3, FFXIII and XV were sideshow laughingstocks in comparison. Squenix has finally realized that they need to course correct away from anime trash if the series is going to regain its relevance, so they're leaving you and your childish sensibilities and preferences behind. Thank god!