I'd love it if we got more limited item clothing and accessories. It'd be great if we got a wider range of dress-up items for limited offers and if the offers had more different items for sale or if they changed more often.
Maybe there could be 3 items at sale every time: 1 basic item for cheap, one really nice item for medium price and one supercool premium item, that would be more expensive. Often limited items turn up useless because everybody and their momma buy them, so you get no advantage. You just wind up competing for one global spot with everyone else wearing the same thing. That premium item would be something rare (like the cupcake dress). Some fashion games already have these luxury items, it's time we get them in our fashion houses too. :)