Since this thread was resurrected by someone that wasn't me for once, I'll chime in!
It seems to me like the concept of a soulstone would work much better if it wasn't just a generic crystal. Cases in point would be the Gem of Shattoto and the machinst's aetherotransformer. The Black Mage quest line shows that when one pushes thaumaturgy too far, the flow of aether in and out of the body will burn you, but there are specific means of filtering that aether in a safe manner—the/a Gem of Shattoto, a heat sink in essence. Most of the Goldsmith Guild's early quests were about using materials and gems to act as aether conduits for the thaumaturges. It's all worked into the lore of the game how this artifact would work. In the instance of the MCH's soulstone, it's implied that the 'core' of the aetherotransformer—specifically how the device pulls lightning-aspect aether from your body to power your skills, is the soulstone itself. Which also makes sense because it's literally letting your essence pass through it. Spiritbinding taken to the logical conclusion.
Same goes with the Crafting Plaques. They're a physical representation of one's skill and notoriety in a field and can very well collect a certain 'essence' over time.
The problem comes in instances like Paladin. Where it was essentially: "Hey kid. Wanna be a fighter for truth and justice? Take this rock."
It seems to me like the concept of a soulstone would work much better if it wasn't just a generic crystal. Cases in point would be the Gem of Shattoto and the machinst's aetherotransformer. The Black Mage quest line shows that when one pushes thaumaturgy too far, the flow of aether in and out of the body will burn you, but there are specific means of filtering that aether in a safe manner—the/a Gem of Shattoto, a heat sink in essence. Most of the Goldsmith Guild's early quests were about using materials and gems to act as aether conduits for the thaumaturges. It's all worked into the lore of the game how this artifact would work. In the instance of the MCH's soulstone, it's implied that the 'core' of the aetherotransformer—specifically how the device pulls lightning-aspect aether from your body to power your skills, is the soulstone itself. Which also makes sense because it's literally letting your essence pass through it. Spiritbinding taken to the logical conclusion.
Same goes with the Crafting Plaques. They're a physical representation of one's skill and notoriety in a field and can very well collect a certain 'essence' over time.
The problem comes in instances like Paladin. Where it was essentially: "Hey kid. Wanna be a fighter for truth and justice? Take this rock."