I'm interested in the concept. All fighters have 'em. I tried googling this, and it was all based on the Arcade version. Since I don't play the Arcade version, this is upsetting. So, here we are. Cool.
So, here's how I'm gonna do this. Ranking based on character type. The closer to the type, like Vanguard: name, the better over all. Not to say that any character is BAD, but that others are more over all useful in most situations. Some characters have a very, very specific niche to fill that sets them apart from everyone else, so pray don't take this as a de facto "these guys are good, these guys aren't" list.
Here we go!
Vanguard: Cloud of Darkness, Sephiroth, Firion, Cecil, Warrior of Light, Garland, Cloud.
Why? CoD is just...punishing incarnate. Sephiross over here can block attacks and debuff anyone near him. Firion is a beast on the ground and not too bad in the air (but seriously play him on the ground he's amazing), Cecil is just unpredictable as he can go from air to ground to air and back quickly. Warrior of Light is an all rounder. Garland, though, he seems to be all about brute force, but is easy to block as he telegraphs heaviest. And Cloud, he's amazing until AFTER he attacks, where he's wide, wide open (seriously, he charged up, and missed, so he's dead meat unless he dodges and starts HP spamming).
Assassin: Kain, Squall (if you are doing the trigger right, which is tough online cause lag exists), Kuja, Lightning, Zidane, Squall (if you just cannot use his trigger, ever), Dad of War/Jecht, Tidus, and Noctis.
Kain is amazing all around, and like Zidane but better. Squall is a beast if you're using his trigger but otherwise, he's unremarkable. Kuja is a close range marksman, and a terror who can ruin days (I can barely beat him as a Crystal bot, same with Kain but for different reasons). Lightning is the wild card, as one second she's swinging her blade around, then next thing you know, she's casting a spell then bringing the pain to the wall. Zidane is just bad on ground, but a god in air...His HP Attacks are more mind game-y then the rest of the Assassins. Jecht only has his block going for him, so he's basically a Trigger!Squall, but watered down. Sure, he hits hardest, but at what cost, right? If you aren't using Tidus as a dash blitzer, please keep him in the air, as his ground game, unlike Zidane, is pitiable...Nothin' else to see or say here. And Prince Noctis...Discount Guy Lightning who only has range thanks to Warp over Lightning.
Trap/Troll!Marksmen: Kefka, Emperor. DPS-Master!Marksmen: Shantotto, Ultimecia, Terra, Ace. Combined!Marksmen: Golbez, Y'shtola.
So, since Marksmen are the most varied, I decided to split 'em all into separate kinds. Easy enough, I figure. Anyway, for the trappy/trollish ones, let's get them outta the way first. Kefka is chaos incarnate. I never know what he's gonna do next, and his run animation is just...makes me wanna murder him. Emperor is slightly more trappy than everyone else, but not a pure troll like Kefka...He's a pain, as most of his spells/skills are traps. Makes sense knowing what kinda person he is from FFII, but he's a high skill, is freaking annoying, kill me please, kinda character.
Now onto the offensive ones. This was tough, as every marksmen have at least one trap-like skill in their arsenal. Shantotto brings the pain. Her skills are all about the crowd-control, and she excels over everyone at it. And her skills are the most potent out of the marksmen. Ultimecia........I don't know well how to describe her, but she's just the troll DPS marksman. She has the most trap-like skills out of all of them. They all hit almost like trucks, due to sheer amount of her projectiles. But, and this should be obvious, if face-to-face with any other type, they suffer greatly (and are likely to die) at melee. Terra is only stronger than Shantotto when Terra goes into Trance, but when she's in human!form, she's a weaker spellcaster than Shanny. She has that dash-attack that is pretty dope, and most of her skills can be spammed...but stop attacking for a bit and she becomes a heavy hitter due to how charge skills. And Ace is the longest reaching other than Ultimecia. He doesn't have the troll-factor down. His cut cards skill gives him the most skills in the game, but from what I've heard, it's pretty random what color his cards become, so can't rely on them.
The "red mage" of the marksmen are my favorite. Golbez is pretty beast at mind games. Other than Emperor, and Kefka, he's a little bit of everything. Y'shtola, on the other hand, has a 50/50 on traps and damage spells. She has debuffs out the wazoo, however. Her HP attacks, while flashy, are either a boon, or a curse. Holy is great for getting people off of you. Vivifying Lance is a supportive characters wet dream, as it heals on hit (sure, it's 500 or so, but that adds up with things like HP Regen). Holy Snare is a trap. And her final one is for when you're getting charged at.
Specialists: Exdeath, Bartz, Ramza, Onion Knight, and ya boi Vaan.
Exdeath can block EVERYTHING at C. Lv. 10. That alone makes him the best specialist. And just like Light, he has modes, which varies his play style up. One is more melee, while another is about debuffs. He's a real threat, no matter what. Bartz can literally do it all. His best HP attack, in my opinion, is his Dancer skill. Seriously, he Segata Sanshiro's you to death. Maybe he's the most LGBTQ+ of all the characters, for his Dancer skill alone, who knows. Ramza is a medium threat base, he can pepper foes with Stone and Ultima from afar, while if he charges at you, you're likely to be hit. He can buff himself for extra range and damage, or can buff his allies for extra damage. When he, himself, is buffed, he's one of the strongest offensive characters in the game. His Stone becomes Spirit Bullet (no joke, that's what it is called and I love it), and has more range but less tracking, great for rushers and blitzers alike. His Ultima gets more AoE-y on impact with others or ground. His melee's get double range, just about. And since he can charge his EX Skill (Shout/Galvanize/Focus), Bahamut is useless on him, so bring buffs or debuffs and pick Leviathan or Ramuh to take advantage of that. Onion Knight is another wild card. He's either a Ninja from Hell, or The Pope, and both can easily ruin anything, like Bartz can. His Ninja and base can hit the most outta any character but each hit is weak, where his base and Sage can fling spells. His main gimmick is "use skills for Ninja, spells for Sage", so the more of one you use, the more good at that he gets, to simplify things. And Vaan....I don't think many like his HP Spammy gimmick. He's probably the strongest base Specialist in the game, for the simple fact of "land HP Attacks enough and they hit harder". He's the only character that SHOULD be spamming HP Attacks. I mean, not exclusively, but still....Use them after a single wall combo, you won't regret it.
Anyway, that's it. I know, I might have placed people in wrong order or places, and I apologize. But, and I literally cannot stress this enough, this is based on what each character can do, and how good they are at that. If I were biased, Ramza, Y'shtola, Lightning and Terra would be first in their sections, for how good they can be if used well.
This isn't meant to be taken seriously, but to start a discussion, if at all, so speak your mind on it, okay?
Hope you all enjoy this!