I would be very careful what you wish for.
I would say the character and spirit of this post can easily answer your own question.
First of all, if you think everything that’s art should be technically (in your ideals and archetypes) perfect, maybe you should consider engineering instead.
I think if someone asks for a crit give it to them. If it’s obvious they are trying very hard, but just can’t do the amazing things that some of the group can, well then you have to make a decision between giving them encouragement/criticism that’s relative to their skill level and potential or telling them that maybe they should consider another form of expression. I would say that that’s a hard call to make considering how much is based on personal preference.
Sometimes a piece that isn’t technically great may be truly inspired or capture an overall atmosphere or effect. It may be amazing to some while other find it does nothing for them.
Art is about many things. Whether they overlap or come in groupings isn’t relevant. Any one thing can stand on it’s own if it’s effective in that one thing.
Also what is good for the goose is good for the gander. If you decide to be overly blunt and crude about someone’s attempts be willing to open yourself to that same thing.
Some people react best to gentle motivation while other crave knowing all the gory details and feel that all criticism is good criticism. I find it’s best to deliver everything with a bit of tact.
But now that you have shined such a hard light, I would hope that you are open to that same scrutiny.
If you really want to test your awesomeness with a group of fairly blunt folks, go post your work at conceptart.org. You mind find yourself longing for the slightly more nuanced approach of fellow zBrushers.
Cheers,
holto