I think Laddy largely stated my personal wants. May still give this a shot with a few things not directly mentioned or elaborated.
X - Thou shalt allow the player to play the game: Seriously, let's stop with A.I. party members. If you're going to stick to it, then do it like XII where I can switch over to them and still manually control everyone if I wanted to, and give me a Gambit system to program the A.I. But also I want to extend this to the dungeons and story. I want more interactivity, pace cutscenes better, give me dialogue choices that can slightly alter the story, give me short but fun mini-games that merge with the story (think Cloud doing CPR in VII or Celes fishing in VI). I don't need another 40 hour game that is split between non-interactive cutscenes and traversing uninspired dungeons.
IX - Thou Shalt spread the side quest wealth throughout the game: Easily my biggest pet peeve in Final Fantasy, DO NOT LEAVE 90% OF ALL THE OPTIONAL CONTENT TO FINALLY UNLOCK WITH THE FINAL DUNGEON. I don't care how epic and wonderful you feel your world and story are, sometimes, I like to take a break and do something else for awhile. It cleanses the mind and gives me a chance to chew over the story and characters, instead of just constantly trudging forward with no real time to just sit back and reflect. If the plot is good enough to keep me hooked to the end, that is fine but still you should give the player the option to do something else from time to time.
VIII - Thou Shalt make the Sidequests have meaningful story purposes: No more MMO style "go collect x amount of y" or "kill a amount of b" I don't mind Mark Hunts but I need some story reasons to go after this creature and I want it to involve actually talking to more than one NPC and I want it to have the party get involved.
Example:
DO NOT DO THIS: Player enters town, see's a character with a question mark over their head.
NPC: Hello traveler, I need your help, my son went to the cave over yonder and has not returned, I fear he may have come in contact with the evil Killer Bunny. Could you please go check up on him?
Player goes to cave, finds Killer Bunny, fights and kills it. Unlocks Datalog entry about the Killer Bunny.
Jimmy: Oh thank you traveler, I was exploring the cave, looking for some moss gto use as fertilizer for my dad's farm, when the Killer Bunny attacked. Now I can help my dad, here have this: RECIEVE MOSS ITEM.
DO THIS INSTEAD: Player enters town, overhears a conversation or starts talking to NPCs
NPC: Hey, did you see Farmer Brown? He rushed past here a awhile go with a concerned expression. I wonder what's wrong.
NPC: What am I going to do? I lost another shipment to that blasted Killer Bunny monster. I told the convoy to avoid it's lair but they took that damn shortcut anyway.
Merchant NPC: Tell me about it, I tried to hire some guys to pick up some of the caves moss for my shop, but that damn monster mauled or scared off anyone I sent to the cave.
Player wanders town, here's more stories about the moss, the monster, and Farmer Brown, until player finally meets up with Farmer Brown at the town entrance.
Father Brown: Oh what should I do?!
Player talks to him
Player: Hey, you alright, you look a bit worried?
Father Brown: I... I can't seem to find my son Jimmy. He was helping me plow this morning but we had to take a break because I ran out of fertilizer.
Female lead player: He might just be out playing
Male lead: Yeah, you're right, he's a young kid, he's probably just out playing with his friends.
FB: That's what I thought too, but his friends haven't seen him since this morning either. I'm worried something may have happened.
female lead: Well, we'll ask around town and see if we can find something.
FB: Can you? Oh thank you for helping me!
Player party explores town and asks questions, finally the merchant npc mentions talking with Jimmy this morning about the moss that grows in the killer bunny cave. They tell Farmer Brown and he flips out, runs after his son. Party travels to the cave where they finally meet FB and his son, but they are being cornered by the Killer Bunny. The party fights the KB and whoops its ass.
FB: Oh thank you travelers!
Female lead: No problem
Secondary party member: We couldn't just let that monster eat you both up.
Jimmy: I'm sorry daddy, I was trying to get some moss for the fields and sneaked in when the killer bunny was out, but it came back before I could sneak away.
FB: That was still reckless son, I'll puniash you later, but for now I'm just happy that you're safe.
Male Lead: Well, all's well that ends well.
FB: Thank you travelers, here, take some of the Moss my son got from the cave. It may not seem much but this moss can make anything grow big and strong.
Secondary character: *suggestively* Anything?
Female Lead: *smacks secondary character* get your head out of the gutter...
*party receives moss*
END EXAMPLE
The Quests should have a story focus as well, and it should be well written enough to be mistaken for being a part of the main plot.
VII - Thou Shalt let the Player Explore!: Xenoblade has changed me, while I have never been terribly bothered by the lost of the world map, I am terribly bothered by how lackluster world area designs have been for Squenix. I do no want a pretty but terribly linear and empty world like XIII, and while XII had a nice MMO style design, let's face it, Xenoblade is a game changer and the idea I'm restricted from climbing, jumping, and swimming on the world stage is just not going to cut it. Especially since Xenoblade allowed me to do all this in a world that is larger than XII's Ivalice and it was on the Wii, a console every modern gamer is always quick to point out its inferior output. XIII on the powerful next gen consoles gave me mostly a pretty tube.
Xenoblade gave me a world
Basically, if I can see it, I should potentially be able to reach it and interact with it.
Though the main thing to understand about Xenoblade's dungeon design is that it mixes both linear and open world styles. Some dungeons and cave are fairly linear, but open spaces tend to be huge and have tons of secret passages and nooks and cranny's to explore. It's all about balancing and using both for their strengths rather than one being superior to the other.
VI - Thou Shalt have Humor: Seriously, when did FF get so serious? I mean if you compare the amount of times X, XII, and XIII tried to make you laugh as opposed to IV-VII its pretty staggering how serious the series has become. Humor is great for a variety of reasons, it allows the player to bond with the characters more, because we get to see another side of them. It also creates more contrast for the player and keeps the drama from overloading the player. We also need this to come from the party, kooky NPCs are nice but sometimes they can undercut the world and mood of the story. Instead you should just stick to the principle that most of the party and game cast can stoop to humor, even the bad guys.
V - Thou Shalt Have Challenge: Seriously, we need to make these style of games a little more difficult. I get you're trying to keep it easy cause you're more focused on narrative but let's face it, these are games and not interactive movies. I hope SE learned from FFXIII that fans are not going to take the bulltrout of making the series into just about the plot and realize we want a game in there but more importantly I feel its time we need to make the games main campaign more challenging. I can't fathom why this is so difficult to do. I mean if your point is to keep the narrative flowing then take a lesson from Atlus and the Persona games and just add difficulty modes, I mean for smurf's sake you already do it for Kingdom Hearts, why not FF? The other issue here is that I feel you need to find new ways to make the games challenging instead of just upping the enemy stats, raising item prices, and lowering how much gil and XP you get. All you really accomplish is just making us work longer for the same types of battles and strategies. Let harder difficulties allow enemies to utilize different weakness and abilities, it should change how we approach fighting them not just level grind a few extra hours. Regular encounters should not be something the player dreads, you should make it one of the more fun aspects of the game not just a means to an end...
IV - Thou Shalt have real Job Classes: Don't ever do FFXIII's bulltrout MMO wannabe "class" system. I want real classes, give me a thief, or a dragoon or a black mage, not a character who does DD magic damage, a melee character who happens to have a flashy attack that looks like Jump, and a class system where your ony options are hit it with a weapon, cast a spell to hurt it, cast a spell to debuff it, cast a spell to heal you, cast a spell to buff you, and block with your face. Those are not what I consider to be classes and I don't know why you feel the need to emulate the MMO community who simply use said terminology to break down and organize the game's actual honest to god real classes that can actually do more than the six things I mentioned above. I want abilities, they are the spice of life and keep the genre from being boring. I mash X because game developers don't make games that offer a need to use anything more than that, but I don't actually want to be mashing X, I want to feel the need that skills like Darkness or Jump will turn the battle. I want to feel like Blind and Silence are important. I want to anguish over having a Time Mage for Haste and Slow or having a White Mage with Shell and Protect, not just "Buffing Class". I like having Thieves who can increase my loot and get me a cool item long before I would naturally get it. I love Blue Mages for the shear variety of their skills and the challenge of getting all their skills. I want to see Dancers and Geomancers who are collage of various class traits in a single package and weigh them aginst the traditional single skill classes. I wand to do more than use Attack and Magic -> Cure spell and if you are making the games more challenging you need to build strategies around making the player use these skills instead of making them window dressing to make the character a little less generic.