Racial abilities are a reflection of lore because of the history of that race and
the remarkable peoples that express their skill or talent for something
over multiple generations.
Every MMORPG
have reputation systems. Humans, who created the Sacred Order would
have decent bonuses on these reputation systems. As the Children of the Gods they could also have a passive boost to healing and other health point regeneration abilities that are placed on or given by a human character - such as eating food, healing spells, patching someone else up and feeding pets. This would suit priest healing, paladin healing, paladin tanking and warrior tanking.
Scars of Honor could also add a unique twist to the genre by tying racial active abilities with the current class. This would add a little more complexity and add more differentiation in the same class by selecting a different race. Where the same class has 1 active ability based on which race was selected.
For humans only I am thinking these active abilities are:
Warrior: Cleanses health debuffs and decreases current cooldowns on survival/tanking abilities.
Paladin: Provide the Paladin and allies a shield blocking some amount of damage to HP.
Mage: Increased mana/resource regeneration and boosts shield amounts.
Priest: Increases healing and shielding provided by the Priest.
Pirate: Increased mana/resource regeneration.
Necromancer: Summons and pets will have massive health regeneration.
These are just rough ideas tying what the class could do and what the race is known for which is life and living. In most of these cases it involves protecting or regeneration HP. For the Mage and Pirate it reduces the stress of resource management since these would probably be considered DPS characters.
I look forward to seeing what others have written and look forward to writing more about the other races!