I don't really get this mentality. Every FF entry, especially starting on the SNES, has been fairly different. 12 had major gameplay differences but so did 10. And if 12 just had a normal ATB system I don't think anyone would be saying it isn't FF-like. Some FFs are very high fantasy, some are very futuristic, some are closer to our real world, some are very far from it. Everyone has different preferences of which FF is their favourite because of these differences. There isn't really a right or wrong answer though. FF very quickly became a series that was diverse with each entry. And that's how it should be. The bigger problem is in the 90s it was a nearly-annual franchise. Since FFX we've had only 4 mainline games, two of which were MMOs. Because of this not all of the various types of FF are really being serviced. If you didn't like 12 and didn't like 13 and didn't play the MMOs...FF has basically been dead to you for 15 years.
The thing is with continuous changes there is very little if any concept of maintaining a level of consistency or familiarity. I mean outside of a few notable stables such as Chocobos, Moogles, Cid, and some monsters that have been carried over from title to title, outside of this on some games in the franchise one could easily change these aspects, give it a new name and the typical RPG fan would be none the wiser it was a FF game.
With series like Dragon Quest, fans know what they are getting, the series is consistent that one could play the first game and the series and the most recent single player installment and see while there are significant improvements in the mechanics, the core that defines as Dragon Quest game is still there.
If one was to play the very first FF game in the series and then play the most recent single player mainline installment, there is very little elements that are retained if any at all.
It's fine for a series of improve and progress over time. However the problem with constantly trying to reinvent the wheel and make something drastically different than the previous game is over time you lose the familiarity and core concepts start to become something unrecognizable.
With the FF series you are never guaranteed what you get and because of huge overarching changes from setting, gameplay mechanics, and even to the point of a genre shift from turn based RPG to a hybrid semi-real time to full real time to even action. It can be said that nothing is truly sacred when it comes to the FF series.
Sometimes change for the sake of change isn't necessary, retreading an old concept that works well and refining it can work well too.