Well, I am certainly a neophyte in woodworking, but let me open my big mouth anyway.
In the design area, I know nothing but would like to see more posts regarding proposed works. I enjoy Mark's postings of famous woodworking artists. I don't always like what I see, but that is me. An idea that might be helpful is a simple set of references regarding pleasing ratios and a few design rules. This reference could be a sticky that Marks maintains and updates as new questions arise. Also include Mark's recent postings regarding types of joints and items of that nature.
The design forum I equate to the front door of project. On the back door I suggest a critique forum. It would be of course be totally optional. The 'user' would post to the general forum of his choice for sharing his work with the members of that forum. Then if he was seeking critical constructive comments, he put a one-liner in the critiques forum asking that people take a look at his posting on the xyz forum. This critique posting would say that yes, I want you to comment on the design, I am opening myself up to criticism and I will not get insulted. Likewise it is the responsibility of the critic to be constructive and detailed in their analysis of what they like and don't like.
Certainly the 'front door' and 'back door' ideas could be in the existing design forum. Maybe it is just a matter of encouraging people to ask for design critiques.
As a famous news analyst would say, ' what say you, tell me where I am going wrong.'