I guess it's the tone, now if you said something like:
"It looks good, but it would be even better if you........."
And not in ways that alter the actual art itself, but the way it looks.
Sometimes a change in color, contrast, and brightness do make it better, but what I see and what you see might be a little different. I can understand lines and bleed-overs in the skins, those are just oopsies.
I'd admit, some of the figures do look waxy. But if it's done as ART, then it's my art. If it's retouched, then it's retouched art.
However, I do appreciate constructive criticism, as long as it does not sound condescending.[8D]