I've thought of a couple ideas before and i have a few more to share too!
[Edited by Professor Greyrose - the idea you posted in this paragraph is completely inappropriate for Wizard101. Please consider the audience of this game before you post ideas such as this again.]
Plain Islands In every world there are houses you can craft or buy related to them, but what if you had an island without a house. Just a plain island with maybe a river and bridge. Then people can do what ever they like with it for parties or maybe make a mini houses out of crates!
No Hat Charaters be able to not wear a hat, instaid when you unequipped your hat it you can choose to go without your hat or with the one you start out with in the beginning.
Sitting I've seen people post about being able to sit down on a couch item, or a chair, [again - please think before you post - the remainder of this paragraph was edited by Professor Greyrose due to inappropriate suggestions]
New Houses Like in crab alley and in some celestian areas you can swim underwater. Make a house with an area like that. Maybe recreate the Playhouse from Wizard City to have the playhouse underwater. Start a whole new collection of underwater items that can only be used in underwater areas of houses!