MP is mostly annoying when you're tracking hundreds of points of it. If you made Fire cost 1 MP and scaled it up from there, a first-level caster could have like 5 MP and you could pretty much put them on Sorcerer casting without exploding into stupid amounts.
Then you optionally let people multiply MP and costs by 10 when writing it on their sheets (so that first level caster writes "MP: 50/50" and lists "Fire: 10 MP") for the Authentic Final Fantasy Experience. Just the same as how players might want to multiply their HP by 100 on their sheet, and multiply all incoming damage by 100, such that when they have 50/50 HP and get hit for 12 damage, they go "Okay, I had 5,000/5,000 HP, and I take 1,200 damage".
I know someone who actually did that for a D&D Psion, just so they could be "all Final Fantasy-like". She did it ironically.
Anyway, here are what I consider the key things of Final Fantasy, that you need to consider if making a FF game:
- That fucking victory tune. Put it on your phone and play it after every fight.
- Specific creatures exist: Chocobo, Moogle, Cactuar, Tonberry. Optional: Moomba.
- A stronger version of an existing spell goes AGARAGARA (Fire, Fira, Firaga, Firaja in FF12?) because Fire III apparently sounded too much like a game mechanic rather than something people said in-game?
- Most characters end up with some form of "pick different bags of abilities". FF5 and X-2 have job-changing where you can keep one or two cross-class things, 7 lets you glue shiny balls to yourself, 10 lets you wander about on the Sphere grid (is that was 12 basically did too?), 8 lets you junction different monsters and such, blah blah blah. Tictacs does the sub-classing thing, as does one of the MMOs. So some form of "I am a fighter but also I cast this type of spell" needs to be available.
- The players start off thinking they're plucky rebels against a megacorp, government, kingdom or whatever. But then partway through, SURPRISE, they actually have to go and fight a SUPER SPESHUL AND UNIKE villain who wants to destroy the world.
For casting spells, I would probably divide them by level into various chunks like so:
Fire Spells: Fire (1), Fira (2), Firaga (3), Firaja (4), Flare (5), Meltdown/Beta (6)
Then do the same for Water, Ice, Earth, Wind, Electricity, Gravity, Time, Sealing, Affliction (put Poison in there rather than 3 Bio spells?), Boost (Barriers and shit), Curative, Healing (status+resurrect)
Classes then work like spoilered for length:
The Black Mage gets a basic progression where at level X you learn level Y spells of all schools you have unlocked. Then their progression is "Level 1: select 3 schools from Fire/Water/Ice/Electricity/Earth/Wind". At level 2 you let them have another of those or Gravity or Affliction. After a few more levels let them take another choice, adding Seal to the mix, then give them another choice after a few more levels and so on. Then at [High Level] you say "You learn Ultima because you're a Black Mage".
A White Mage starts with Curative and "Healing, Boost, Sealing - select two". They can eventually unlock Gravity and Time but get more class features to make up for the lack of schools available, and end up casting Holy.
A Red Mage starts with "Curative, Boost, Healing - select one" and "Fire, Water, Electricity, Earth, Ice, Wind - select one". They get a lot of things to choose from, but fewer actual slots with which they can make choices, and also don't get an ultimate spell. Chuck in better combat prowess (in the sense of general numbers).
Then if you really want you can specifically make, say, a Time Mage that starts with Time and Gravity, then gets a bunch of Class Features where their Time spells affect heaps of people at once and last longer, or they learn special Time spells other people don't get, and they can teleport and shit.
You then have the chassis where a Mystic Knight is a Knight or Fighter who chops off a bunch of their Fighter/Knight abilities, has more generalist numbers, and gains a couple of magic schools, slower spell level access, and has special unique class features, and so on. And then making "The Affliction Mage" or "The Dark Knight Cecil" is really easy.
And with that, you can seriously just let players swap one or two things around to emulate what most of the games do. This works even better if you take Weapon Techniques and put them into schools with levels - considering a FIGHTING MAN has some combination of [Power Break, Armour Break, Magic Break, Resist Break, Blind Attack, Slow Attack, Paralysis Attack, Death Attack, Petrification Attack, Poison Attack, Silence Attack, Rage, Double Attack, Triple Attack, Quad Attack, Slash All, Flash, Throw Item, Throw Cash, Assault, EVERYONE FRENZY!, Dispelling Attack, Confuse Attack, Barrier-Slicer, Vampiric Attack] before we get to the spell channelling, or Thief/Alchemist/Gambler/Monk/Ninja skills or whatever.
If most abilities are put into "schools" like that, then it becomes easy to give choices in the classes, let players swap a few things around, make new "multiclass" classes, or whatever.
