I forget where I read this (and I may be wrong), but my understanding is that Final Fantasy and Dragon Quest are two sides of the same coin for Square. Dragon Quest is the 'safe' franchise with a defined aesthetic, setting, and style. Dragon Quest is a series where each came is very much in sync with the other.
Final Fantasy, on the other hand, is the 'risky' franchise. This shows in that each main installment takes place in its own setting, with its own characters, gameplay, aesthetic, etc.
I bring this up because I don't think the question gets to the heart of the matter. Final Fantasy can do traditional fantasy, sure, but it won't go back to its 'roots' because the entire point of the franchise in its current form is that it's free to do whatever. There's only a few key elements that go from game to game, and its setting/aesthetic aren't among them. If a FF16 does traditional fantasy, rest assured that a FF17 wouldn't.