I'm newish, so some of these may be things I just haven't discovered/figured out yet. So, apologies in advance if that's the case. 

-Email notifications for PMs. I need things to yell at me so I don't miss them. x.x 
-Ability to have a PM be in reverse order -- I'd love to be able to have the newest post at the top of the first page. 
-Additional folders for PMs. It would be cool if we could make our own or have one for IC and one for OOC for sorting purposes.