I am in favor of expanding the available color list and removing the most similar colors. Based on the actual color data that I looked at for numerous colors (red value, green value, blue value, hue, brightness, saturation, position on color wheel, names of similar color hexes, etc), the two pinks (rich rose and hot pink, in klutz's list) were the most similar colors on the list. So, I proposed removing 1 of them. You can see how that went.
I don't see a rationale to keep both pinks but not add desirable colors with decently greater difference beyond resistance to change. In fact, IIRC, there are a few color pairs using current colors that are more similar than any color pairs using the new colors.
Also note that the new rainbow organization of the color list makes color similarity a lot more evident compared to the less aesthetic and more chaotic previous organization scheme.
Regarding adding colors; it is a nice QoL feature to have more colors to choose from. A LOT of people like being able to choose certain colors and don't like being stuck with certain other colors. This is true for games of all sizes; people are just more likely to get stuck with an undesired color in games with larger player counts and with smaller color lists. The recent PR added some nice colors (it had also removed some colors, but those removals were reverted).