I think that some of the best aspects of the game are flawed, or needing improvements. Here are some things I think would work well in the game, without taking anything away.
Last online. Something for the friends tab, this is good if you haven't seen a friend on in a while, and want to know if they aren't playing on that character anymore, or if you just keep missing each other.
Leave a note. Something else for the friends tab. This is good if you want to tell your friend something like "Hey! I just got my Lil' Siren to adult, we can hatch now!" Without having to keep checking the tab.
The word "Trojan". It's one of my biggest pet peeves that the text chat filter won't let us say the word Trojan. I don't exactly now why this isn't allowed, but I'm tired of talking about my wooden horse pet.
School Wallpaper. You know the wall paper inside the Ravenswood classrooms? I think that would make a really cool housing decoration.
Arena Furniture. I understand why you can't place furniture in your private bundle arena, but could you let us do it a about a meter from where the field spawns? I think it would be really cool to put some of that Avalon weapon racks down. At least let us set teleporter destinations there.
Gammas spiral. You know that massive 3D model of the spiral in Gammas room? Can anyone actually say that wouldn't be the worlds coolest house decoration.
Stop moving the camera up. When your placing furniture nowadays, the camera angle moves up quite dramatically; to the extent that it actually inhibits decorating.
I love the first two. It would be useful to see who's playing and who's not so I can delete people, and being able to message someone when they're not on (to tell them to meet me at a certain time, perhaps) sounds really useful.
The "Last Online" would need to be carefully implemented to make sure it did not undermine the "invisible" settings. Some folks just want to go unseen while they train some pets, complete solo quests, deco a house. Or maybe they just want to login, check gardens then log out. I, personally, wish you could access the "seen by friends" controls prior to actually logging a character in. I am not unfriendly. I just do not have the time sometimes to spend any of it chatting or answering questions, visiting, etc.
The mailbox idea has been the subject of many threads for quite sometime I think.
I have always noticed items in the game that I stopped and thought... Wow that would make a very nice house deco item. But they can't be picked up. There are dozens of these items in dungeons everywhere. I am all for changing that.
As far as camera angles go... grrr. This is probably the issue that has aggravated me the most since day one of playing this game. They are simply horrid at times. Your issue is deco which is, indeed, a valid one. Mine is other things. The most annoying? In battle angles. Never a day goes by that I do not wish for a static camera setting in options. Or just the ability to zoom out or even just raise the top edge a bit. All the swinging around and zooming in of the camera when spells are cast. Some of this is fine but most of it is just uncalled for. Or the constantly bad angle, when fighting larger creatures, that prevents you from seeing the damage numbers and other info that appear above the targets head when they are attacked. It is ridiculous that such a simple problem to fix has been allowed to persist for so long. Also... Why can't we look down? How many times have you stood on the edge of somewhere and wanted look down to view the scene below?
I like the ideas. I don't know anything about houses or furniture though but the first 2 ones about friends is great. I've been missing a friend who I was close with for a while now and he lives in another time zone so I don't know if we're just playing at different times or what. Hope KI uses your idea :)