First of all, Monk talents would be adversely affected by fatigue using the following formula *(1-(fatigue/100)). In other words, if you're running around with 17% fatigue your abilities will only be at 83% strength. This would affect the Martial Arts Training tree (which will be generic) and all Monk class trees.
Secondly the Monk would have combination moves and finishing moves. Finishing moves would all have a status ailment attached and the duration of that would be based on the number of combo points. Combo points not used or added to within two turns are lost. In any case five combo points is the cap.
Finally the Monk would be able to Grapple. Pinning foes and having attacks that can only be used on pinned creatures. That'll be it's own tree.
As for some tree ideas.
Martial Arts Training
- Unarmed Strikes: The Monks 'weapon'. Putting points into this increases your base damage (a formula based off strength would probably be good, otherwise a Monk could dump all of their points into this for the first few levels and effectively have an end game weapon. Optimally it should take 5/5 Unarmed Strikes & 40+ Strength to get to this point).
- Avoidance: Increases Defense. What's mentioned above about scaling applies but based off Dex instead.
- Iron Skin: Armor talent, seeing a pattern

- Conditioning: Provides some elemental resists and some bonuses to saves. Scales off Will.
Combination Strikes (combo builders, all scale off Dex)
- Combo String (Basic strike but w/scaling damage, no cooldown, builds one combo point, it does cost Stamina which is what separates it from 'attack')
- Double Strike (Builds two combo points, attacks twice but second strike is weaker, like a dual wielded strike)
- Whirlwind Kick (Attacks all adjacent creatures. Puts one combo point on each creature.)
- Flurry (Builds one combo point per talent point invested, longish cooldown compared to the rest of the tree)
Finishing Strikes (damage scales off Str, talent points, and combo points. Other effects just off combo points)
- Stunning Fist (Pretty much like every other stun attack but the number of rounds scales off combo points)
- Shattering Strike (Sunder Armor, amount scales off combo points)
- Vital Strike (Blinds the target, duration based off combo points)
- Finishing Blow (damage is multiplied by combo points)
Grappling Techniques (While a grab is maintained you can not move without breaking the grab but you can attack and use other techniques)
- Grab (Grapples the target (becomes pinned), more talent points along with strength increases the strength of the hold and initial damage inflicted. At level 5 you can grab two targets. Duration is based on the strength of the hold vs. monsters strength)
- Choke (Can only be performed on a grappled foe. Constricts target and inflicts damage every turn it's maintained. Damage and amount of air lost per turn is based off strength and talent level)
- Maim (Can only be performed on a grappled foe. Damage inflicted that reduces attack power. Damage based on str and tl)
- Gouge (Can only be performed on a grappled foe. Gouges a target in a vital area, inflicting lots of damage and possibly blinding it, stunning it, pinning it (seperate pin from grab), or confusing it for a few turns. Damage based on str and tl)
That's the basic tree outline. An advanced martial arts techniques tree could be a level 10 tree with APR and Crit for Unarmed Strikes and some other stuff, maybe spell dodge. Haven't really put much thought into that one yet.