The combat rules have changed quite a bit, though most of the changes have been around the edges. It all started when I tried to design Yags statistics for characters such as Azumi and Beatrix Kiddo - I needed to decide how to handle the differences between Western and Eastern fighting styles, which led to defining unarmed combat styles.
Eastern styles are not seen as special or mystical, just different. Kenjutsu emphasises speed and combat against lightly armoured opponents. Western styles have evolved to fight against (and with) heavy armour.
The introduction of unarmed combat rules has had an effect on the whole combat system. This was necessary in order to keep things simple without needing special rules just because a weapon isn't being used.
I have changed the name of two attributes recently, to make them better match what they represent, and also to simplify the display of character stats.
Each of the primary attributes now starts with a different letter. This allows attributes to be listed using a single letter without worrying about confusion. The attributes are now: Strength, Health, Agility, Dexterity, Perception, Intelligence, Empathy and Will.
Charisma was changed to Empathy, because it has come to be more an ability to understand others, rather than an ability to get on with others. The latter is better represented by the Charm and Guile skills.
Stamina was changed to Health principally to give each attribute a different letter. However, it de-emphasises the 'strength of will' side of Stamina, and this can be placed entirely on Will.