This is the great thing about these boards - ask a question and you get a multitude of good responses to choose from!
I agree that corruption tends to be about the otherworldly / eldritch, but the RAW implies that people can get it for doing evil. It is perhaps too strong of a penalty for breaking a binding contract. But since it can be removed, it is not necessarily a long-term problem. However...
The idea of treating binding contract as an obsession I think is great. I had not thought about that for non-Sorcerors, but I think it fits well. Now what kind of penalty / bonus to give for the effected character? -1 to Saves / Attacks when not pursuing the contract; +1 when actively working on it? I don't think you want to make it too strong a penalty / bonus, just something to make the character want to complete the contract. Perhaps keep it in place for a period of time if the Temptress dies at the hands of the PC to prevent 'accidents'?
I agree that corruption tends to be about the otherworldly / eldritch, but the RAW implies that people can get it for doing evil. It is perhaps too strong of a penalty for breaking a binding contract. But since it can be removed, it is not necessarily a long-term problem. However...
The idea of treating binding contract as an obsession I think is great. I had not thought about that for non-Sorcerors, but I think it fits well. Now what kind of penalty / bonus to give for the effected character? -1 to Saves / Attacks when not pursuing the contract; +1 when actively working on it? I don't think you want to make it too strong a penalty / bonus, just something to make the character want to complete the contract. Perhaps keep it in place for a period of time if the Temptress dies at the hands of the PC to prevent 'accidents'?