The big problem with critiques is that the people who need them most are often the ones who are least willing to listen. I was doing critiques on the Leica stand at Arles a few years ago and someone showed up with a load of non-colour-corrected photocopy-quality images, six or eight to a sheet of A4, in no particular order. I am not exaggerating. She sincerely believed that this was all she would need to get a book contract. No proposal; nothing.
When I said that the pictures needed to be in order, she said, "The publisher can sort that out." She said the same when I tried to suggest that the publisher would also need to believe that the pictures were of adequate technical quality to reproduce: "They can correct that."
The pictures were completely unmemorable in any case, but many (?most) photographers have difficulty in separating
their investment in a picture (it was hard to take, it was their kids, it took a lot of post processing) from what anyone else is likely to see in it. Suggesting that they try to look at the picture as if they knew nothing about it will result in a blank stare.
This is why I don't do critiques over the internet, especially on open galleries that invite comments from all comers. It's too time consuming; there's too great a risk of being misunderstood; and there's always someone ready to attack
you personally or as a photographer: "If you're so great, why aren't you...?"
There's a piece on my site about the different things people look for in critiques:
http://www.rogerandfrances.com/subscription/ps critique.html
As I say in it:
Critiques, appraisals, assessments, portfolio viewings, call them what you will: at their best they are invaluable, and at their worst, they are an embarrassing waste of time.
Responsibility for success and failure is equally shared between the critic/appraiser and the photographer. It's true that some critics are inherently better than others, but it's also true that some photographers make the critic's job a lot easier.
Cheers,
R.