I am sure Roll20 already captures a lot of statistics, but it would be nice making those stats available for various functions. Like it would be nice on my profile to see how much game time and dice rolls I have done per game I have played, average rolls, etc :) Some stats that is also useful to manage inactive players is the ability for the DM to mark the start and end of a session and then get daily, weekly, onthly stats per player to say how active % the player was (being in game) and how many posts/rolls was made on average per session, etc.
