I think if an artist wants constructive feedback they should state what they were aiming for in the image and ask for advice in the description section of the upload. If the artist's intention is unclear, most times the people giving feedback are just telling the artist what the critic would have done...projecting their tastes onto the artist's work. If an artist uses renders without shadows but is happy with that, it's a waste of time telling them to turn the shadows on....that's how the critic would render their own art, so it's not really giving helpful advice. I think the problem in the galleries most of the time is bad communication - of what the artist's intent is so that they can get the feedback that will actually help them. My two cents