It would be nice if you could see items you owned, and+or you'd added to your wishlist.
It would help resurface items in my WL. Sometimes I can't justify a purchase because I'm not sure what I'd wear it for and with. This happens especially with special shop items, because I'll really like something, but it will be too expensive to get one in every color, and I'm not sure which color I'll use yet.
I usually open up the filtering, to show items I don't own, when my outfit's close to completed and I can't find something that matches for one of the layers. In that case showing every item on the site is mostly too overwhelming to be useful. If I could narrow it down to things I'd already decided I was interested in buying it would help.
