TS4 definitely should have shipped with a BodyShop equivalent, since they were going back to limited swatches instead of continuing with Create-A-Style. I think the only reason why they didn't do so is because some suit at EA was like, "But if we give them the ability to create infinite recolors of base game content, then they'll be less motivated to buy DLC!" (Which is totally bogus, because the DLC still comes with new meshes for hair, clothes, and objects...) And, you know what? I'd be quite happy to see BodyShop make a return. I used to spend hours upon hours recoloring hair styles, eyes, skins, and clothing and putting my favorite anime characters on T-shirts in that thing!
If they REALLY want to appeal to that 12-18-year-old female demographic, an upgraded version of BodyShop that allows for custom recolors of CAS and Build/Buy objects would definitely heighten this game's appeal to that audience. Most girls, from the nerdiest to the most mainstream, love to customize things. We alter our clothes, we dye our hair, we paint our nails, we get tattoos and piercings (sometimes behind our parents' backs...), we hang lights and/or flower garlands on our beds, many of us go through a "put stickers on everything" phase...That's why TS4 needs its own version of BodyShop, as well as paintable ceilings (because the plain, white default ceilings don't work for anything that's not emulating some cheaply build, lazily designed modern building ). If you want to appeal to a female demographic, customization is a feature that's more than worth investing time and money into.