I've always found the colours not to be overly important, other than the front face of the phone, since it is in a case 99% of it's life. With the camera bump it's almost a must to have it in a case anyway. I did always like the colours of the early iPod Nano though, still have my 2 gen one, too bad it's buggy and crashes all the time.
Now if Apple could get the battery life of the Apple Watch to match an iPhone we would not need these huge phones anymore, say this only because I miss how small the nano was, and that it was never noticeable in my pocket.