Altcoins? Sure, your players will be so happy to see PD accepting altcoins.
PVP/Multiplayer? You had it in the past, but as I remember it was being used by some users to abuse your free money (faucet/giveaway). So you need to have a better system for this one if you are going to relaunch it.
Improved stats/graphs? I do not think it is an urgent thing to do. I would suggest you to work on something else especially the jackpot. Make it automatic please.