Look to this topic for previous discussion on lightsaber forms: Lightsaber Form Idea
This is somewhat of an extension of the discussion that relates to lightsaber forms and how they interact with armour. While lightsaber forms would remain catagorised within the lightsaber skillset, each form could also have a linked and locked in armour requirement.
To keep initial implementation basic:
The forms could be implemented as stances similar in operation to the precision, balanced, and shield oath stances already in-game.
Armour N/A: The character can be considered in the Shii-cho form while wielding a lightsaber without a more advanced form/stance active. No additional technical implementation is necessary, since the The Determination Form can be considered a fallback that all trained in lightsaber usage can employ due to their basic training.
Heavy Armour: Soresu can be used as a heavy defense form jointly with heavy armour to produce ‘tank’ melee play. The technical implementation can be +Enmity and +AC at the cost of -AB and/or - Physical Damage. In this way, it functions like NWN’s Improved Expertise feat.
Light Armour: Ataru is up for this one to serve as an assault form intended to pressure an opponent. Implementation can be +APR and +Physical Damage at the cost of -AC and/or -AB. In a way, it can function like NWN’s Improved Power Attack Feat.
Force Armour: Shien is suitable here as the premier Blaster Deflection form designed to protect ‘caster’ type force users from those pesky blaster bolts. Implementation is +Saber Deflection (Affects the ‘Deflect Blaster Fire’ perk specifically) and +FP damage at the cost of -AB and/or -Physical Damage. The form could function similarly to the Empower Spell Metamagic Feat in NWN.
I’m not certain where in the skill tree they should be accessable from, but none of them should be available from skill rank 0. I recommend a minimum of Rank 25 before they become available.