I could go on for literally hundreds of thousands of words on why XIII was a failure and how to improve a sequel, what it comes down to is adding depth of interactivity in 3 layers. Gameplay depth (strategic and fun battles, and lots of minigames), world depth (lots more towns, puzzle dungeons, vehicles, exploration, real-time physics and lots of items and locations to interact with physically etc.) and writing depth (things like radiant AI, meaningful enemies not just monsters, conversation options and plot choices like WRPG's have).
XIII failed at all of these things. Gameplay? It was merely pressing X and paradigm shifting occassionally. Took away nearly every layer of battle strategy. No limit breaks, no MP, no stealing, no armours, no formation setting, no ability system (crystarium is actually replacing the leveling system which had always been automatic and seamless before, but now it wastes 3 hours of your time pointlessly as it's linear and there are no interesting abilities anyway) and I could go on and on. There's only a few battles in the entire game that are difficult or fun to do (mission 64 really is the only one that is both imo). The equipment system was horrendous. There were no minigames except a pointless chocobo item grinding one and I guess the robot stomping one that only lasted about 30 seconds. The world? Most linear and underdeveloped world I've ever seen in an RPG. No towns turned a great culturally adventurous series into a primitive dungeon crawler with style over substance cutscenes. The writing? Really really bad plot, ok characters (I actually don't mind them, I think they were just handicapped by being in such a horrible game with such a bad plot and poorly developed world) and no interaction with the writing. Least characters in a FF game since II I think, every other one had 2-3 times as many main characters, and far more meaningful NPCs. The couple of FFXIII levels where you could chat to people may as well not have been in the game.
I like modern & sci-fi/realistic settings for FF (like VII and Versus), but I don't mind IX's setting either if it has the depth and detail the series deserves. What I don't like is the meaningless quasi-futuristic nonsensical fantasy worlds of X and XIII and to a lesser extent XII. Those are resorted too purely out of laziness. They don't have to be coherent at all in terms of technology or style and they mix together any random looking crap and the dress sense of characters has been horrible since X but that's just Nomura's true style coming out.
XIII is a really lazy game, everything about it screams laziness. Can't make towns in HD? Lazy. Even low budget RPG's have had towns. You had 5 years and $60m budget what the fuck were you doing with it? Obviously the employees have no passion for their job anymore. Can't make a meaningful plot without invoking 5 million gods to explain away the horrible level design and "destiny" theme? Lazy. Can't make a deep battle system so just chisel every bit of complexity the series has accumulated until all that's left is choosing a job and clicking autobattle repeatedly because that's quick and easy and looks cool in a trailer? Lazy. Can't add any minigames? Lazy. Can't add in proper limit breaks? Lazy. Can't add more than 6 party members or 6 summons? Lazy. Can't add any side missions other than tedious meaningless battles against almost entirely palette swapped enemies? Lazy. Can't develop luscious immersive graphics and instead have what looks like an upscaled ps2 game with extremely low polygon environments and nonsensical linear paths but it's ok because the cutscenes look great? Lazy, but people seem to think the graphics were actually good for some mind bogglingly ignorant reason. Compare Gran Pulse's sterile empty landscape to far cry 2 or Uncharted. Even XII had more realistic looking environments. Can't make any writing interaction at all because cutscenes are easier? Lazy. Can't create a decent ending that makes sense? That's not just laziness, that's incompetence as are most of these and I could go on...
FF should become more like yakuza, gta, fallout or mass effect. They're all significantly different game design wise, but they all have interactive depth and a focus on engaging story that satisfies in different ways. I don't mind if the next FF is not the best game ever, I just want it to be engaging and not the most tedious and painfully dull game ever made like XIII. Just give the series to someone who still cares about making games and doesn't just want to cash in on the brand. The yakuza devs would love a chance at a big budget game.
Keep the Cait Siths and Umaros and Quinas out of muh game
Different races bring the world to life and add interesting cultural variety. XIII was free from these and it was one of the many many reasons it felt so lifeless and dull. Maybe you simply meant over the top cartoonish characters which would be fine, but XII has the most varied races of any FF game and I don't want only humans.
