I wish we would get more swatches for hairs and skintones...
Hair Swatches
Black: We need different undertones for black hair. The current one has a blue undertone and I think a little more neutral and darker black swatch would be a welcome change. The salt&pepper swatch is decent but it doesn't always work well for younger sims because the silver hairs can be very strong on some hairs.
Brown: The dark brown swatch is one of the best swatches in the game because it looks good with pretty much any hair. That being said, we could use some more undertones for brown. The light brown swatch looks kinda obnoxious on a lot of the hairs and I wish we would have ashier tones.
Red: I don't personally have complaints on the red side but someone else probably does.
Blonde: As someone who has naturally blonde hair, this is the category that really irks me. The swatches are awful. The ''dirty blonde'' is the only decent blonde swatch and it's not even a real dirty blonde. I have never used the cheese swatch because I hate it with a burning passion. The platinum blonde swatch looks good on very few hairs because it looks choppy on a lot of the textures. I wish we would get ashier tones for blondes. Something that resembles actually dirty blonde hair. I have the most basic blonde hair anyone can be born with and there's no way to replicate that in the Sims without custom swatches (and I don't like using custom swatches)
White&Gray: Personally, I don't mind the darker gray swatch but the lighter one I have a slight problem with. I wish we would have something a little lighter with less blue undertone.
Unnatural: I wish we would have a broader range of unnatural swatches. For example, dark purple, lighter green, pastel pink, pastel blue etc. because we're really lacking in those.
Skintones
I don't even remember what most of the swatches look like because I had to replace them with custom overrides because the dark tones had very weird textures and undertones. Some of the darker swatches are almost corpse-like because they have so ashy undertones. Skintones are probably always gonna be an issue unless they create a slider with undertone options and then a broad range from light to dark.