For me the most defining part of FF is that it puts storytelling first. A final fantasy game tells a deep story dealing with philosophical dilemmas.
The gameplay is not that important since there are only a few enemies in the game who are really difficult. A final Fantasy game is not about making a hardcore difficult JRPG or about being able to spend 100s of hours exploring. Its about creating a world and telling you a story that should make you think about life. FF 13 was not different in that approach and I am sure that FF 15 will also tell an interesting story.
Lets be honest, most of the random enemies do not require any strategies to beat. With the exception of Boss Battles you can pretty much spam normal attacks and succeed. Most of the time you will not have to micromanage because you will probably never have a shortage of potions etc. And even the hardest enemies often can be beaten with a simply strategy. A FF game can be beaten by anybody who puts a little effort into it.
There are JRPGs out there who have brutally difficult boss fights, needs several hundred hours to be beaten and you have to know every detail of the battle systems to succeed... FF takes a different approach and puts its focus on storytelling... and thats why Square wants everyone to be able to see the ending sequence. The final story boss is never the hardest enemy in the game.
Somtimes people argue too much about graphics, gameplay, difficulty, etc... Some games simply put their focus on storytelling and I absolutely love these games. Heavy Rain, Assassin's Creed, Heavenly Sword.... there are so many games that get bashed for gameplay or difficulty reasons because some people simply can't see that the most important factor in game design was storytelling.
Storytelling is something that is not valued very much by many. There are even games that sends you through randomly generated dungeons in search for randomly generated loot in a gamewolrd that offers a generic mainquest and is centered around hundreds of meaningless sidequests for a character that you created yourself that has no real impact in the story... I am really happy that there are games like FF who take linear storytelling very important and who offer a great gaming experience.