Adding Pirate101 rewards to Dueling Diego was a great addition, but what I personally think is missing a Grub Guardian equal caliber game for Pirate101.
With all the recent discussions on crafting for Pirate101, I think a Grub Guardian like game that rewards crafting materials, reagents, or even crafting experience would build upon and set apart from crafting in Wizard101. Just like Grub Guardian, this crafting game would tie directly to your Pirate101 characters so you could work on your crafting levels or even build housing items (or houses!) on the go with mobile devices.
Most of the sandbox games out there require a desktop, console or laptop to play. This would be one of the few for mobile platforms.
This obviously wouldn't prevent players from crafting within Pirate101, but would change how players do it outside of the game (just like pet training in Grub Guardian).