The piano/keyboard isn't my main instrument, but I'm not sure that the color of the keys would make a huge difference. Practiced/professional violinists, for example, don't use sight to figure out how to place their fingers, and pianists don't even have to worry about tuning the way violinists do.
The two people above you are pretty much saying the same thing. Piano keys being unmarked and making sense to pianists as the best way was being used as proof that using keys not marked with arrows could be the best way for editors. I'll throw in with agreeing as well, my piano teacher hated when music had finger numbers on it and things like that, using them just slowed you down and messed you up, especially when the hands changed positions. Labeled piano keys would be bad because it would prevent people from learning the right way to play.
You would only really need a reference point every octave. I've always felt that having "sharp notes" on, basically, their own row of the piano was silly, and I've speculated on how one could design a sane keyboard that puts all (musical) keys on an equal basis... In short, the black (physical) keys are part of the madness. ;)
