I see pros and cons for both the gallery model and forum model. So, I think maybe we need both working in conjunction. 

In the current system's favor... 
I've noticed on at least three of the recent submissions that someone not listed in the critique sign up thread posting honest commentary. In a way, I don't think it can be helped. If you arrive at an image after 50 oohs and aahs, you're probably going to either fall in line and ooh and aah or  leave without commenting. When people click on an image with a full critique in progress, their reaction seems to be critique or defend (or leave no commentary). 

It's immediate

It keeps the reaction and commentary with the image (or fairly close to the image). If the commentary runs to multiple pages, I would imagine that you can click for a full screen of the image. 

The system notifies me once when someone from the critique group posts an image. With a unique forum wouldn't we be getting notifications with every post to every thread? That sounds pretty overwhelming to me.

On the other hand, what's not working for me using the Gallery model...
You can't comment on an image more than once. 
You can't edit your comment. 
You can't interact with the artist-- except in a private im. (I get as much from the critiques of other's images as I do from the critique of my own.)
You can't interact with the other critiquers for clarity or exploration of why they feel the way they do.
But the biggest issue is, that if you try to implement suggestions from the CG, then you have the dilemna of what to do with the initial image. I'd like to get rid of it, on the other hand, I don't want to lose the information that's now attached to it. If I just replace the image, anyone that's commented on the image can't comment on it again.

With a forum model, any image that you don't really feel is finished could be posted in the forums and then you could upload the finalized image to your gallery. 

Just my .02
Pearl

kalonart.com