Calculating Defense when target is unarmed.

Okay, can you clarify how to determine a target's defense in the following situation?
It says under the description for Dodge that it should apply for ranged attacks and it says under the description for Parry that it should apply for melee attacks if the target is using a sword or shield. And, there are talents for allowing unarmed parry, or using parry for some ranged attacks, or using your Dex modifier with parry.
However, if the target is in melee, but unarmed and does not have any talents that would affect the situation, how do you calculate their defense? Would their defense only be 10?
We came up with a house rule that a character in melee could use Active Dodge, but they had to sacrifice their next move action and retreat 5 to 10 feet from the attacker. It made sense that someone should be able to use their Dodge, but they couldn't stand toe-to-toe with an armed attacker without giving ground. Does this sound reasonable?
Also, should someone with Savage Chi be able to 1) parry weapons with their arm/hand or 2) use their active dodge in melee without a penalty if they spend at least one CE? Or does this make Savage Chi too powerful?
It says under the description for Dodge that it should apply for ranged attacks and it says under the description for Parry that it should apply for melee attacks if the target is using a sword or shield. And, there are talents for allowing unarmed parry, or using parry for some ranged attacks, or using your Dex modifier with parry.
However, if the target is in melee, but unarmed and does not have any talents that would affect the situation, how do you calculate their defense? Would their defense only be 10?
We came up with a house rule that a character in melee could use Active Dodge, but they had to sacrifice their next move action and retreat 5 to 10 feet from the attacker. It made sense that someone should be able to use their Dodge, but they couldn't stand toe-to-toe with an armed attacker without giving ground. Does this sound reasonable?
Also, should someone with Savage Chi be able to 1) parry weapons with their arm/hand or 2) use their active dodge in melee without a penalty if they spend at least one CE? Or does this make Savage Chi too powerful?