I think it would be really nice if we get our own small house in the personal instance that we can customize.
Items like furniture and decorations may be world/instance specific drops or purchased from merchants requiring either gold or something else. There may be item rewards tied with achievements as well, lets say Master of Arah will reward you with a Lupi statue you can put on your desk. Kind of like GW1 HoM where you could put a statue when you’ve beaten UW,FoW, DoA ect.
I imagine RPers will be happy to get housing and invite friends to RP with there too.
There’s also the option to put expensive/limited furniture in the cash shop with gem purchases as well.