Ever since I learned that I can skill swap, fights got a little bit easier, cause I can customize load out and specialize each member for a role they seem to be great for.
Before I start there are a few things that can determine what skill you can use in battle.
1. Weapon: Different weapons have different stats. As well as skill slots. Without any skills slotted in, a character cannot even attack in battle. Assuming a sword has Fire slot, Fire magic can be slotted in, but it would not help a Fighter much because its damage is based on MAG. What you need, would be Fire Edge, a melee attack that derives its damage from ATK (physical attack basically). Or, instead of an active skill, you can also slot in a Fire-based Passive bonus. Like Power UP to increase your ATK further. Others like Lightning passive, would increase your HIT (Accuracy)
2. Character Type: Default skill slots. Some chars are genuinely good at what they do. While some are hybrids. While others kinda...suck.
Here's some of my personal build that I'm trying out.
You ask, why do you have multiple Double Edge? Well, that's because you can only use a skill once per attack chain. So having 3, Leo can actually chain 3 Double Edge in a row if he has 24 AP.
Now for terrible character...
Luana is pretty terrible when she joined the party. She is ... still terrible now. While she has a mix of Earth skill on her weapon, and two Special slots (Steal, Trick Hit), 1x General and Fire.
Let's review her skills:
Earth (MAG-based)
2 Specials (Not really based on anything, it's mostly there for effect, not damage)
1 General (ATK-based)
1 Fire (MAG-based)
She has to be a mage. But the problem is, other mages like Zerva and Vira do better damage and have better slots.
True, Vira might be slower than Luana (MOV 2 vs 4), but it still doesn't make sense for me to rebuild a lvl 6 mage when I have a level 12 by the time she joins. And her General skill is a wasted slot.
Vira can even equip a sword if she wants to. And comes with 2 offensive slots by default. Earth and Extra (in this case, Impulse) I know she's always last to take her turn, but with formation bonus, she never gets to cast anything on her round anyway cause we blew it on the first turn for an alpha strike.
Zerva in comparison, is only slightly slower (MOV 3) yet pack 2 Darkness slots and Fire. While it's true he does have 2 nearly useless Power slots, his higher level makes him a better choice for me in the long run. Luana just can't catch up. She's 6 levels lower than everyone else when she joined FFS. A he's surprisingly quite durable.
And when you wanna compare her with Fyuria, Luana is just gonna fall far, far behind in the flexibility department.
I may have made a mistake in giving Fyuria high AGI but she needs those AVD (Dodge), then you swap her Light slot from Ascension to Heal... and voila: you have a healer that can cast Heal 3x a turn with the right formation bonus. She has the highest SP in the party. Her two Combo slots is shit, but at least her weapons have enough magic slots to compensate. Don't even think of putting a single point on STR (you can, but she'll never survive a beating in melee range) Let her sit back and spam Thunder (chance to paralyze), Wind (chance to make target sleep) twice per turn from the back row.
She can now replace Ellis as primary healer of the party.