I remember trying out the color slider mod for the sims4 from thepancake1 and MizoreYukii and I have made some zois in Inzoi as well (which has a color slider and pattern mechanic).
Being able to select colors for clothes is incredibly useful when combining clothes from different packs, but it can be a bit time consuming. A a lot of clothes in the sims4 are also so stylized and often has their own patterns. So let's say you take a top from... I dunno, Eco Lifestyle which has a lot of colors that are a bit muted and the clothes also show that they are made of recycled materials and you want to combine it with a bottom from another pack by using a color slider and being able to choose the pattern. Now you have to spend time to make your pants in a muted color and you also need to choose a pattern that makes the pants look recycled. While it's cool that you were able to do that, very often than not I just tend to select some pants that work well enough with the top, or I just select some bottoms from that Eco Lifestyle Pack.
In InZoi (which has a color slider and you can also make your own patterns or use existing patterns and swatches) it makes more sense because the game has layered clothing and the clothing looks more realistic and it also has many basic clothes with and without patterns. You can often make exactly what you want and you have so much more options.
I often used the color slider in inzoi (I found it especially useful for Jeans because a lot of Jeans are just different shades of blue) but I didn't use the pattern feature much because I'm finding it difficult to make good patterns but some people on inZoi have made some great looking patterns. In Build/Buy in inZoi the color sliders and pattern mechanic is incredibly useful when building, because now you can combine any build/buy item with another because you can select the same pattern but it also takes so, much, longer to build.
So all in all, I would say that color sliders and being able to choose pattern would offer more options that would increase the longevity of the sims4 and help you with creating what you want. It would especially help for some clothing like Jeans.
But you are still able to do a lot with the swatches that are available as long as you don't want anything specific and are fine with the more stylized clothing and build items in the sims4.
