I think an in-game e-mail system is a great idea, in fact, I was just wishing PL had one the other day. That being said, I doubt STS wants to store all of that potential data or load the systems down with all of those extra database calls. Of course they could streamline and limit the system to control both of those concerns. Based on their lack of interest in further development to PL, if this ever happened, it'd probably go to AL, if any of their games got this enhancement.

At the end of the day, for those that you really want a way to communicate with when off-line, it might be best to just connect with them on some type of social media or instant messaging service.