i'll reiterate - it would be up to those who would use a forum to cultivate & nurture that forum's environment... and it would require a certain amount of active participation, commitment and dedication [as much as time demands can afford, mind] from those that wish to get something out of it...

how i envisioned others using a critique type of forum would really not be that terribly different from the way the galleries are being used: a person posts, those that have something to contribute & offer do so, the poster chooses to either rework & repost or to not do so, etc...

however, there would be room for more in-depth discussion about a particular image someone wants help with should a person desire it...
it would allow for others not in the "group" to readily access ideas, suggestions, etc. to help them improve their own artwork...
it would allow for posting/housing outside links or new discoveries that could be of benefit to anyone...

i was thinking of things in terms of a centralised open study group type of thing
i was thinking that the enthusiastic interest as expressed in this thread for learning & growing as artists could be powerful enough to support a forum [support meaning enough people who would participate]

i could be wrong in my thinking...
not the first, nor the last, of that i can definitely guarantee...