The Final Fantasy series that I am writing is a mixture of technolgies. Chapter 2, which Zannith is creating, is futuristic, while Chapter 1 is somewhat medieval. All parts of the saga are in the same tmeline, just different planets.

Personally, I prefer a mixture. Having guns is boring, but having just ancient technology is pretty boring too. FFIX was my favourite Final Fantasy, and it wasnt purely ancient civilisations. It would have to have a world map, with at least two worlds. FFV was cool, how it had three worlds. The villain... well not another crazy fool would be nice, but I would love to see another female villain, like Ultimecia and Edea. People like Sephiroth are getting very old now, it seems like every game has a Sephiroth clone now. Personally, ExDeath was my favourite villain.
However, my favourite Final Boss isnt one from a FF game. My favourite Final Bosses are Mithos form Tales of Symphonia, and Indalecio from Star Ocean 2.

Personally, I don't really like having the Job System, because whats the point of having a multitude of characters? I mean, FF5, Faris, a pirate for most of her life, decides, "To hell with this, im going to be a White Mage and help people!" Each charcter should be unique, and have a lot of charcter development. FFIX was great in this regard. Apart from FFIV, this is one of the very limited FF games where each charcter is unique.