It's really nice to get a perspective from soneone who does 'real' art. Last year I was working for an artists' collective and there was no way I could persude them that digital art was 'real' They would take a photograph, bring it to the studio and copy it! Where's the art in that - technical skill certainly but imagination - no way. I think what you have said goes a long way to defining 'good' art - although it is always in the eye of the beholder. I would add 'balance' to your list of criteria. The colours, the light and shade, the fractal shapes - they all have to look balanced - I don't mean symmetrical - just all in pleasing proportions. Hope this makes sense.

We don't cease to play because we grow old, we grow old because we cease to play.