I agree with the comments on the rating systems - I think they are poorly used when offered (generally - people either rate them good or not at all, who rates a picture 'very poor'? most people would just ignore such an image).
The binary system also has flaws - for instance, where people have not taken the time to select the 'like' button it can be misconstrued as 'dislike'
I do like the flickr method of groups. You can start a group, invite similar minded / capable people into the group and then vote or comment. This limits the number of images a member has to view / comment on and photo's are added to the group specifically to be commented on by the members. It's more like a large number of virtual camera clubs.
The forums can be used like this, or at least I do
Phil