I'd like the fashion career to come back, especially if the have the top model and designer branches. I'd also love the idea of saving styled looks, even just for personal use but gallery too be great.
I also love if with we could pick the secondary colours and colours of hair accessories that are attached to the hair. So many times the hairs have great highlights/pop colours/hair ties/scarves but not in the colour I want for the main hair colour I happen to be using. I wouldn't need a paint tool for hair that just seems a bit much, but more hair colours added I think could easily be a free base game update, and the secondary/accessory colours could converted to the swatches currently locked to specific hair colours—to be unlocked for any hair colour. But this could be paired with the fashion pack.
But if I could I'd probably want the future pack the most.