You already can do that. We call them 'traditions' rather than styles, though.
They are still pools to pick from. I was looking for something more like predefined list of picks to make. For example, a player says, I have no time to think it through, but I want to play a Muhammad Ali-type of character. And then GM replies, pick a Boxer trad, and remember, this is a fantasy game - you'll be punching through steel armor soon.
Pools and long lists of choices are fine, it's just that when you're playing a game for the first time, it is simpler to start with something decent and default instead.
As for the document - it's very chaotic. The list of Focus Features for example, is alphabetical, but Requirements create their own order. It is also not clear which abilities are offensive, which are defensive, and which are utilitarian. It gets worse when you consider how many different special abilities are available:
Adroit Defense, Martial Arts, Exertion, Combat Maneuvers, Exploration Knacks, Adept Archetype, Focus Features, Battlefield Etiquette, ...
Someone really needed to go wild while building the class. It's really confusing.
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To be constructive, here would be my take on the organization of the document.
CLASS FEATURES
(add Exertion here)
(add Exertion recovery here - for short and long rests)
MARTIAL SPELL USES/LEVEL (a table)
(Martial Spell is a vancian system for tracking usage of special abilities)
MARTIAL SPELL LIST (well, it should be renamed to something martialartsy)
(list martial spells here - put ALL abilities here, from Adroit Defense, through Flurry of Blows, to Diamond Soul and other fancy stuff that is still mostly inferior to arcane spells)
(martial spells should have a few tags: Offensive, Defensive, Utility, Physical, Spiritual, Wondrous, Exploration)
(Physical are feats of body, Spiritual are feats of will, Wondrous are just that - wondrous and go beyond simple trained abilities)
(each martial spell should list Exertion cost to re-cast it during the same combat or scene)
Examples (note that recast is possible only during the same combat or scene one has used the ability - if you have only one instance of a Flurry of Blows in your martial spell slots, you will be able to use it during a single combat only):
Seven-Mile Step (level 5; Exploration, Utility; action: none; duration: 5 minutes; recast: Exertion 1)
Travel a path with a single step.
Multiply the distance traveled by your proficiency bonus.
Flurry of Blows (level 1; Combat, Offensive; action: attack action; duration: attack action; recast: Exertion 1)
Overcome by overwhelming them.
Gain bonus action usable only for making melee attacks.
Tougher than Rock (level 3; Combat, Exploration, Defensive, Utility; action: reaction; duration: until the end of the next round; recast: Exertion 1)
My body is my shield.
All damage taken is halved.
MARTIAL STYLES (name + list of Martial Spells):
Boxer
Commando (soft plus vital strikes plus stealth)
Hard Art (kicks, punches)
Soft Art (throws and blocks)