Looking forward to those changes!

Anyway, continuing with my post above, I'd like to try and translate the Bloodlines system to Original Sin. I'm going to change some names or mechanics, but will try to give my reason for some of those changes later.

Feats

Feats have a direct influence on gameplay. Most checks in the game are made against these Feats. Each Feat is derived from 1 Attribute and 1 Ability Score. They are divided into four groups: Combat, Survival, Mental and Resist. Combat feats obviously focus on combat skills, Survival feats on worldly matters, Mental feats on Dialogue skills, Lore and Magic, and Resist on damage mitigation.
  • Combat
    • Melee (STR + Melee): Modifies damage when using melee weapons
    • Ranged (PER + Ranged): Modifies damage done using ranged weapons
    • Initiative (COU + Reaction): Determines turn order in combat
    • Defense (DEX + Dodge): Improves chance to avoid taking damage from all forms of combat
    • Speed (Armor type): Increases walk speed during combat
  • Survival
    • Awareness (PER + Wildlife): Improves ability to detect monsters that can't be seen (yet)
    • Inspection (PER + Investigation): Improves chance to spot hidden objects and passages
    • Thievery (DEX + Thievery): Improves ability to open locked doors and chests and grants the ability to disarm traps
    • Sneaking (DEX + Stealth): Reduces chance to be spotted while hiding
    • Luck (Items): Increases chance to get lucky
  • Mental
    • Intimidate (STR + Intimidation): Improves ability to force people into agreeing with you
    • Charm (APP + Suberfuge): Improves ability to use your appearance to your advantage
    • Persuade (CHR + Scholarship): Improves ability to convince others to agree with you
    • Magic (INT + Source): Modifies power of magic spells and/or lowers mana cost
    • Lore (WIS + Scholarship): Improves ability to identify items, flora and fauna
  • Resist
    • Bashing (CON + Armor): Reduces damage suffered from blunt damage types
    • Lethal (Armor): Reduces damage suffered from slashing or piercing weapons
    • Elemental (Armor): Reduces damage taken from fire, electricity and other elemental damage
    • Mind (COU + ?): Reduces effect of spells and effects on the mind
    • Poison (CON + ?): Reduces damage and effects suffered from poison

Attributes

Attributes are your classic main stats like STR and INT. They are broadly divided into three groups following the LMK principle: Warrior, Mage, Rogue. Or in Divinity terms: Ways of the Warrior, Wizard and Survivor. Attributes make up one half of a Feat and usually affect more than one Feat.
  • Way of the Warrior
    • Strength: Adds +1 to Melee and Intimidate
    • Constitution: Adds +1 to Resist Bashing and Resist Poison
    • Courage: Adds +1 Initiative and Resist Mind
  • Way of the Wizard
    • Intelligence: Adds +1 to Magic
    • Wisdom: Adds +1 to Lore
    • Charisma: Adds +1 to Persuade
  • Way of Survivor
    • Dexterity: Adds +1 to Thievery and Defense
    • Perception: Adds +1 to Ranged, Awareness and Inspection
    • Appearance: Adds +1 to Charm

Abilities

Abilities make up the second half of a Feat. They are divided into three groups: Talents, Skills and Knowledges. Talents are physical abilities, Skills are technical abilities and Knowdledges are learned mental abilities.
  • Talents
    • Reaction: Adds +1 to Initiative
    • Dodge: Adds +1 to Defense
    • Intimidation: Adds +1 to Intimidate
    • Subterfuge: Adds +1 to Charm
  • Skills
    • Ranged: Adds +1 to Ranged
    • Melee: Adds +1 to Melee
    • Thievery: Adds +1 to Thievery
    • Stealth: Adds +1 to Sneaking
    • Knowledges
    • Investigation: Adds +1 to Inspection
    • Wildlife: Adds +1 to Awareness
    • Source: Adds +1 to Magic
    • Scholarship: Adds +1 to Lore and Persuade


Examples
Let's try and see what stats popular archetypes might like to have:

Warrior: STR, CON, COU, Melee, Intimidation, Reaction, Dodge; can Intimidate
Rogue: DEX, PER, APP, Subterfuge, Thievery, Stealth, Investigation or Dodge; can Charm
Wizard: INT, WIS, CHR, Source, Lore, Persuade, Scholarship; can Persuade
Ranger: PER, WIS, DEX, Ranged, Wildlife, Stealth, Investigation or Dodge; no dialogue skill

Comments

Speed
Speed could be based on Armor type (PC) and race (enemies) -- Light Armor lets you move faster than Heavy Armor; wolves move faster than bears. If it were an attribute, I fear it could dominate all others.

Luck
Not too thrilled about this stat from a gameplay perspective, but if it's in, it might be a good idea to treat it not as a percentage ("You have a xx percentage to be successfull) but like any other Feat to check against. "If your luck is high enough, you will be successful in this situation."

Offense/Defense
Check of Ranged/Melee/Magic against Resistances.

Morale (Party Spirit)
Increases Resist Mind + other bonuses. Could be a global value that changes according to circumstances, similar to Humanity in Bloodlines, or the characters' relationship.

Magic system
In Bloodlines, each character got access to three spells, which have to be increased with Exp points just like any other attribute or ability. In Original Sin, we seem to have lots of skills/spells like in Divine Divinity -- so I'd decouple the stats system above from the skill/magic system and let players increase skills/spells on their own.

HP / Energy Pool
How about ... same for everyone. Warriors get a lot more mitigation through skills and armor than wizards, who would in return need less Energy to cast spells. Skill cost could be reduced likewise for physical stats.

Seeing / Hearing
- Seing is incorporated into Inspection. "Sight range" I would set to a comfortable level for every player, as I don't think it's a very good skill, because most of the it's too low for everyone, meaning the skill would become mandatory and in other words superfluous. I'd much rather see sight range be used creatively to create tension where appropriate.
- Hearing changed to Awareness: notice enemies you can't necessarily see (yet).

Other attributes that could be interesting, but which I couldn't really fit in: Intuition, Wits.