The idea for the mod is neat, but I feel like you missed a great opportunity: the console. Perhaps there are technical reasons why, but it would be so much more interesting and fun to use if the player could use "/color vivid red" instead of having to work through the mod options menu.
It's kind of fun to pick a color, and describing it is too. But you have to exit the options screen before you can even see your results. Don't like it? Back into the mod menu, click the per player tab, find the box for player color, try another one. It takes a lot of the novelty out of it. If it's possible, I think that's the type of change that would make this much more interesting and fun for servers than a simple color picker and be very much in the spirit of why you made it in the first place.