Here is a small compilation of all my suggestions for the kumos wardrobe which I already like quite a lot, but it can be even better. If you have suggestions please ping me and I'll add them to this post!
Don't get rid of the Item Preview once the mouse is not hovering over the item anymore. So pretty much make it like the wardrobe at new.subeta, the item preview sticking even after the pointer is not hovering over the item anymore. This is super annoying and makes the shop search and wishlist buttons useless.
Mockup of the idea:

Show all layers in the menu instead of having us click an arrow to display them, and have them in alphabetical order.
Mockup of the idea:

Let us move the "Active Effects" category so skins and Rachelle's stages can be layered like everything else
Mockup of the idea:

Add page numbers to the navigation, letting us skip to a specific page (or the last page) if we want to.
Mockup of the idea:

Add images of the noses, lips and eyes in the Base Options page, like we had in new.subeta. No mockup, very self-explanatory.
Add the "remove current skin" button to the skins page, saving us time by not having to find the specific skin we are wearing to take it off. No mockup, very self-explanatory.
pardon for the wonky visualizers, I hope they can pass the idea clearly enough. Thanks for taking a look! <3
the overall layout should just be redone to match the layout of the legacy wardrobe tbh.
first off the sidebar and full header really don't need to be there taking up so much precious real estate. as it is, the entire width of the page (and everything above the fold) is taken up by the avatar preview and the worn items list.
that means in order to actually add items, i have to scroll ALL the way down, removing my HA from view; thus i have no way of previewing what a given item actually looks like as a wearable, let alone what it will look like on my current HA. i know i've been playing a long time but i don't have all the wearables memorized like that! then i have to scroll ALL the way back up to see what the items look like on my HA and make adjustments to their position in the list.
i see no reason why these layout elements shouldn't be able to adapt sizes to automatically fit side-by-side in a responsive manner. my laptop screen is not tiny; it's 15-inches (1440 x 900px), definitely larger than what most people use. so that means anyone not playing on a widescreen monitor is unable to properly use the wardrobe.
additionally the horizontal spacing between wardrobe items leaves big weird gaps. i think grids should be grids, with equal vertical and horizontal spacing between elements, so it takes the same amount of movement to reach something to the left or right as it does to reach something above or below the item you're currently hovering over. anything else is uncomfortable to use and look at.
also, i understand the purpose of the "you have unsaved changes to your avatar!" notification banner, but the fact that it appears and disappears depending on if you make/undo changes to your HA means the contents of the page will be constantly shifting, which is INCREDIBLY obnoxious and inconvenient when you're just trying to make your HA in peace.
e.g. i click an item to see what it looks like on my HA. the banner appears and shifts everything on the page down. i decide i don't like the item and want to click it again to take it off. OOPS, thanks to the repositioning, my cursor isn't on the item anymore. i move my cursor to click on the item again and remove it. the banner disappears, moving everything on the page back up. i hesitate and wonder if actually maybe it didn't look better before, so i want to re-add the item. OOPS, guess what, my cursor isn't on it again!
so the warning should definitely be relegated to some sort of FIXED POINT on the page that doesn't affect the positioning of anything else.