Instead of allowing soulstone trade in... Create a tool that allows a character to take on the skills from any soulstone associated with an inactive account. Once the skill is taken, the stone shatters. It would encourage more soulstone purchases to provide a place to store newly acquired skills. A win for EA/Origin which can sell the tool and also more stones. Players gain another way to obtain skills. Full stones with no skill could simply convert ownership using the tool (nice for players). An additinal thought is to allow the tool to could give players the ability to swap a skill from one owned account to another, for the price of a full soulstone. This would be a more complex addition, but doable IMHO.