Maybe a color picker that includes all colors isn't the goal?
When people first start learning digital painting (painting in Photoshop, Gimp, etc), a lot of them draw landscapes with chartreuse grass, because they used the greenest green on the color picker. Artists in other mediums don't usually have this problem, because rarely-useful colors like #00FF00 aren't included in the typical pigment set.
It really depends on your priorities for the use case. Sometimes you want to give as many options as possible, sometimes it's more important to make it really easy to get something that looks ok and hard to accidentally get something overly neon.
When people first start learning digital painting (painting in Photoshop, Gimp, etc), a lot of them draw landscapes with chartreuse grass, because they used the greenest green on the color picker. Artists in other mediums don't usually have this problem, because rarely-useful colors like #00FF00 aren't included in the typical pigment set.
It really depends on your priorities for the use case. Sometimes you want to give as many options as possible, sometimes it's more important to make it really easy to get something that looks ok and hard to accidentally get something overly neon.