My daughter ( who is almost 18 and loves this game) and myself ( I am over 50 and play) were discussing the whole house/castle thing. I am fairly ambivalent towards the castle thing, i have one but use it mostly for teleporting between worlds. Whereas she absolutely loves, nay LOVES!, the castle idea and spends much time there arranging and rearranging items and spends most of her gold on house hold items.
The gist of this threads is a place to possibly throw out ideas for the castles.
She would very much like to see available in the shops things like: Bunnies that move around randomly ( like the butterflies) {I would further suggest, building from that idea- squirrels, birds, ducks}
Also (and i realize its probably to late for this) but how about a fireworks display that you could purchase then invites friends over and set off.