As I see it a lot of issues people have with Legend combat are compounded by a poor understanding of how combat styles work. Now the article in S&P does help and I believe RQ6 will expand on that to make it much clearer. The concept of combat styles is so very different from standard RPG combat that players often have a problem seeing how it should work.
We have the clearly stated extra CA when using a shield or off-hand weapon (bullet points 2 and 3 p124). The unstated implication is that this extra CA is to be used to parry with the shield or parry or riposte with the off-hand weapon. Personally I just allow the PCs to use the extra CA however they wish.
Grabbing an opponent's arm to pull them off-balance or to try and disarm them are legitimate uses of the Unarmed skill with the off-hand (it's a commonly used tactic taught in re-enactment combats). Wearing an armoured or reinforced leather gauntlet to parry or grab a sword is also something that was taught in combat and by sword fighting (defence/fencing) schools.
We have a clearly stated rule about substituting a weapon (p124). How the campaign sets out the combat styles in use should make it clear when a weapon counts as a substitution. If a GM doesn't set out the combat styles and just relies on what is written in the rulebook then they are going to have all manner of issues with combat styles.
As an example here are the combat styles I laid down before starting my current Lankhmar campaign:
Lankhmarian Noble Combat Styles
Military Noble Style – Lance, Sword and Sword with Shield (Lance, War Sword, Long Sword, War or Long Sword & Heater Shield)
Courtier Style – Rapier, Rapier & Dagger/OHW.
Ilthmarian Noble Combat Styles
Military Noble Style – Lance, Sword and Sword with Shield (Lance, War Sword, Long Sword, War or Long Sword & Heater Shield)
Courtier style – Rapier, Rapier & Dagger/OHW, Light Crossbow.
Barbarian Combat Styles - Pick two styles
Cold Waste Warrior Style – 1/2H Axe/1/2H Club alone or with shield, Unarmed. (Battleaxe, 1 or 2H Club, Axe & Shield (any), Club & Shield (any), Unarmed)
Cold Waste Ranged Hunter Style – Sling or Bow, Javelin (thrown)
Kleshite Warrior Style– 1/2H Axe/Club alone or with shield, Unarmed. (Battleaxe, 1H Club, Club & Shield (any), Unarmed)
Kleshite Ranged Hunter Style – Blowgun, Bow or Sling, Javelin (thrown)
Beast Hunter Style – Short Spear & Shield (any)
Traveller Style – Staff, Unarmed
City Freeman
Poorly Trained Militia Style – 1H Club or Short Sword alone or with Shield (Club/Short Sword & Shield (any))
Part-time Militia style – Pole-arm or Heavy Crossbow, Short Sword
Well-trained Militia Style – Long spear or 2H Sword or Pole-arm or Heavy Crossbow or Longbow, Short Sword & Buckler/Target
Rural Freeman
Melee Brawler Style– 1H Club, Short Sword, Club & Shield (any)
Ranged Defender Style – Bow or Sling, Spear (thrown)
Mariner
Seaman Brawler Style – 1H Club, Short Sword, Light Crossbow, Unarmed
Mingol
Mingol Warrior Style – 1H Axe, Scimitar, Lance, Nomad Bow, Unarmed.
All Combat Styles are known at base (STR+DEX or DEXx2)
Non-military Armour is restricted to leather (soft/hard), ring and scale mail in the form of coats, hauberks and greaves. Padded linen hauberks are also available. Helmets are leather (soft/hard), linen or AP4 kettle hats or morions.
Everyone has Dagger as an individual skill at base STR+DEX+10% and can train it higher.
Everyone has Thrown Dagger as an individual skill at base DEXx2 and can train it higher.