Looking at the "real world example", this design looks far from ideal.
The problem is that this isn't a "real world" example, it's just hammering the existing skills(of which I remind you I consider most of to be garbage in need of a rework as well) into a system that's not designed to hold them.
Were my system adopted, each school gets 3(elementalism 4, to account for the 4 elements) basic skills at 1 point investment(Throwing Knife rework example from before), and then those skills are "upgraded" and expanded upon as you unlock more levels.
Example skills each school to start with:
Assassination:
Throwing Knife(1 AP, 1 turn) - deal damage at range without breaking stealth
Shadow Walk(0 AP, 5 turns) - enter sneaking or upgrade sneaking to invisibility until the end of turn
Chloroform(2 AP, 5 turns) - put the target to sleep without breaking stealth
Charisma:
Leadership(1 AP, 3 turns) - aura boosts accuracy of nearby allies
Battle Shout(1 AP , 5 turns) - frighten an enemy
Command(1 AP, 5 turns) - ally gains a damage boost
Cruelty:
Envenom(1 AP, 4 turns) - poison an enemy within melee range, deal poison damage if already poisoned
Strike Vitals(2 AP, 4 turns) - attack with any weapon that causes bleeding
Firecracker(1 AP, 4 turns) - set the target on fire
Elementalism:
Earth Strike(2 AP, 4 turns) - earth damage and an oil surface in a small area
Hail Strike(2 AP, 4 turns) - water damage and an ice surface in a small area
Fire Strike(2 AP, 4 turns) - fire damage and a fire surface in a small area
Storm Cloud(1 AP, 6 turns) - creates an electric cloud in a small area
Marksmanship:
Retrieval(1 AP, 9 turns) - set a 100% chance to recover the next special arrow launched
Long Shot(2 AP, 4 turns) - fire an arrow at double the usual range, deal additional damage based on distance
Ricochet(2 AP, 4 turns) - fire an that bounces to additional targets
Martial:
Whirlwind Strike(2 AP, 5 turns) - strike all nearby enemies with your melee weapon
Crippling Blow(2 AP, 5 turns) - strike a single enemy and cripple their movement
Quick Stirke(1 AP, 3 turns) - perform a basic attack at a reduced cost
Rejuvenation:
First Aid(1 AP, 5 turns) - restore a portion of targets vitality and remove certain harmful effects
Helping Hand(2 AP, 3 turns) - remove knockdown, cripple, burning and restore some armor
Warm Over(2 AP, 3 turns) - remove frozen, chilled, wet and restore some magic armor
Shapeshifting:
Tentaclewhip(1 AP, 6 turns) - swing a mutant tentacle at an enemy, knocking them down
Scissorhands(2 AP, 0 turns) - replace your hands with blades that deal piercing damage and prevent the use of non-shapeshifting abilities or reverse the effect
Body Spikes(2 AP, 5 turns) - consume all armor and deal a portion of it as damage to all nearby enemies
Summoning:
Call Familiar(2 AP, 3 turns) - summons a creature you control to attack nearby enemies
Spectral Sword(2 AP, 5 turns) - summons a sword that strikes an enemy and continues to do so until retaliated against, doesn't count towards summoned creatures limit
Unravel(2 AP, 3 turns) - inflicts magic damage that's significantly increased against a summoned creature
Tactics:
Sprint(1 AP, 3 turns) - double the movement speed until the end of turn
Tumble(1 AP, 3 turns) - evade all attacks of opportunity until the end of turn
Seek an Opening(1 AP, 1 turns) - mark an enemy decreasing their evasion and increasing the damage they take from advantageous(flanking, high ground, backstab) attacks
Vampirism:
Drain(2 AP, 5 turns) - deal magic damage and gain health in proportion to damaged vitality
Draw Blood(2 AP, 5 turns) - deal piercing damage and create a blood surface
Blood Sucker(1 AP, 1 turns) - clear blood from nearby area and recover vitality in proportion to the amount cleared
Not to mention that it's incredibly convoluted. If I need a map and flowchart to figure out what skills I can get, it's probably too complex. Plus, this is the version without number of ability points required to learn the skill.
While I'll concede that the exact details are up for improvement(like adding a school that can hold/enhance touch and bolt spells, instead of making those elementalism hybrids), the system is no more convoluted than the current one, and I'd even say it's less so.
Phoenix Dive is a prime example of this:
It's a fire themed skill that got moved to warfare because warriors need it to walk on fire.
There's things like all the poison magic being in earth, even though, of the ones available, necromancy is the word people unfamiliar with the game would use when thinking about poison or the variety of other skills that really shouldn't be where they are, but there isn't anywhere else to put them, like First Aid.
In the current system some skills are just arbitrarily shoved into one tree instead of another, even when it benefits only from the one it isn't in.
In my system, if you want a skill, you level the trees relevant towards it's functionality, which you can check at the store before you buy the book, so there's no flowcharts involved.
Hell, I'd much prefer a flowchart that offers proper sense of progression, than the current system where one point is enough to pick up a skill "for utility", resulting in everyone having access to the 24/7 stuns and escapes so long as they invest in memory along the way.
