DREWB1442'S PROFILE

author=Einander
My main problem with the skill sets here is that they lack coherent internal themes. With this sort of incremental skill set, where gaining further access to the skills requires you use ones earlier in the sequence repeatedly, you want coherent themes so that a player can decide what they want from the character and specialize in trees appropriately. The first two to three skills in each tree should give me an idea of what the tree is about and what it's useful for at its higher levels.

In the Tales games, for instance, if you want better versions of your Demon Fang projectile, or another attack that does the many weaker hits of Sword Rain, you use Demon Fang or Sword Rain. In FF7, you get Fire 2 from the same materia that gives you Fire. And in Saga games, the weapons have small sub-specialties; Swords and Bows tend to have multi-target attacks, Staves have status debuffs, Axes and Spears are high DPS with few frills...

But here, your themes are all over the place; they seem more based on the flavor of the tree than the mechanics it uses. Martial is good - it's the debuff/status + damage tree, with a skill that complements that well. Ki and Dark sort of have buffing and sacrifice themes going. Sword is just all over the place. (Phoenix Wing smacks of 'well, I have this, where should it go? eh, here will work, I guess' design.)

I'd suggest running with the themes I identified.
Keep Martial as it is; the theme is good.
Make Ki the self-buffing set.
Make Sword the heavy general DPS; give it a strong single-hit attack (high defense enemies), a multi-hit attack (lower defense enemies), an attack-all skill (many enemies), the Quick Hit skill you currently have... Make it so it does one thing, but it can do so in many different ways for fighting different opponents. Depth not breadth.
Make Dark more the weird conditional set. Sacrifices for benefits, preventing enemies from taking certain actions, Ebon Defilement, maybe something that triggers based on dead allies... It's not as directly powerful as the others, but in the right situation it's more powerful. (You'll have to make learning higher levels require less uses here than other trees, though.)

Or run with completely different themes. The specifics don't matter, so long as the theme is well-chosen. Just *have* themes. Internally consistent philosophy makes a real difference.