How about some environmental changes. There could be areas or landscapes where bots can´t fly, like very "windy" ones or the atmospheric gas is to thin for them to create lift...

Actually I don´t care about saturation, black- and white values. The only thing I would like is a slider on an hue scale of a hsv colorgradient like this:

Could you make the Colorselection for trains in hsv / hsl instead of rgb? It is much more intuitive when i want to select my favourite pink hue for my coletrain, because at the moment I have to look up the rbg values all the time. Just a small change, that would make life so much easier