I get what you are saying, but don't all Final Fantasy games have some elements of sci-fi mixed with fantasy? Even the ones in medieval setting?
I believe FF 2, 3, and 5 were fairly generic fantasy for the most part. 1 was except for the time travel thing if that counts as purely a sci-fi trope. 6, 9, I think 11, and 14 were more steampunk than sci-fi to me, 7, 8, 13 and 15 had that more futuristic nearly modern day aesthetic. 10 and 12 felt the most "sci fi" fantasy to me of all of them.
I guess it depends on the definitions of the genres and where they meet. Final Fantasy has always danced around that concept.
For me, 16 has the same extreme medieval-ism the Ivalice world felt like from the Tactics games. And I love it, as I really do like the darker tone, the sword-on-sword clash, sound of metal armor, clicking of heels on stone flooring sound design of this game a lot already and I'm super excited. Is the visuals maybe a bit generic? Eh I can't say. I thought 13 was trying way to hard to be "HD FF7" and thought that was in itself generic for this franchise. The only thing I don't like about the visuals is the way the older MC (the one in the band of mercenaries, with the scar) is too similar to not only the younger MC (the one in charge of protecting Joshua, his "shield" as he called himself) but also to Noctis himself. The "shield" MC I like though, he's not quite Noctis enough so I can see him as being different. He kinda makes me think of a midieval Zack Fair.
As for the plot, it looks like it is shaping up to be a potential revenge story.
Given context clues, it seems there's some kind of "blight" affecting the land, and the missing Mother Crystal seems to have disappeared or been stolen, this not able to stop it. We see mercenaries charged with targeting Shiva's "Dominant", and only that, implying the person summoning her. We also see Joshua (the blonde child) healing someone, and later what looks like him summoning Phoenix. Ifrit is then summoned by a malevolent force, and the two Fire Icons battle it out. At the end, it kinda appears to be Ifrit literally tearing Phoenix apart, which may result in Joshua's death, going into a coma, or capture. Then we get the younger main character, or not-Zack, appearing to tell the older main character, or not-Noctis, he will kill him.
i presume this means the other person is responsible, and this might be a case of one getting revenge against the other, while the other person is trying to do something against the Icons related to this Blight. That's my guess.