The previous color picker has been replaced. There is a feature request to allow the user to select which color picker to use, system or XD:
You could vote it or submit a new idea in UserVoice.
Could you tell us more about which functionality from the old color picker you're missing in the new one?
With the new color picker, you have five different ways to select a color:
So it's already pretty flexible -- but we are planning to continue improving this color picker in the near future. So please let us know what options you'd like to see added!