This is one of the problems that BAR solves beautifully - a player could leave and rejoin later and the game would continue running just fine. An existing player can choose to take their stuff or not, or take it and give it back when the player rejoins. Truly elegant.
I feel like the issue is more that their pathing algorithm is very inefficient. Not sure why using multiple cores would solve the problem if the cause of the lag is that their pathing algorithm is cubic time or something
There are known cases where power loss during a write can corrupt previously written data (data at rest). This is not some rare occurrence. This is why enterprise flash storage devices have power loss protection.