1. Weekly battles/matches/duels (whichever sounds better)- A major problem with wizard101 is the lack of content after you reach max level (the worlds that take months to make can be done in a few days to a week) so I think that instead of getting players to stay for worlds that will be much like the last one it would be nice to have weekly duels. They would be a lot like tournaments but minus the cost and with a lot of different modes. Something like the turn based matches would work a lot better as a weekly thing as people wouldn't tire from the same thing over and over A few ideas for the weekly matches could be: Only allowing 1 pips spells, only one piece of gear can be used, or critical is always 100%.
2. New arenas- This would liven up PvP a lot more and I don't think it would be that hard to do.
3. Better gear drops- After you get a piece of gear you can't get it again. this would slowly lower the number of items you could get until you get the item you want. This would make a lot of people happy and bring players back.
4. Allowing players to change hotkeys- This is self explanatory. It would make controls better. This isn't really needed as I imagine it would take a bit of work to get to function correctly.
5. Open PvP rooms- These would work a lot like visiting a castle through castle tours except it's just an arena.
These are just a few ideas I thought of, if this gets any attention I would be happy to share others that I have.