1. I would love to see some new skeleton key chest rooms (like with the initial release) which contain some nice items. They would be fairly easy to make as they require the creation of no new content other than potential items from the chests, and simply need placing somewhere in the Spiral. It might be kind of fun to make the environment in which the chest is located look unique based on the world or area.
2. For fishing, I would love to have Lucky Hookline's outfit - Fisherman's Hat, Fisherman's Garb, Fisherman's Boots, Fishing Pole and Tackle Box (wand). Would it be possible to get quests from Lucky to catch a specific epic fish or set of fish somewhere in the Spiral with the reward being a piece of gear? The gear might give a small percentage of fishing luck bonus and/or a few energy points. Perhaps they could even include new spells.
You could continue this trend with other fishing vendors. In particular, one piece of gear could contain a banish rank 2 sentinels spell which a lot of people seem to be having trouble with in Zafaria.