i would give a lot of reasons why people don't use it, but it wouldn't count cause it comes from my personal experience. in my opinion, don't just say "give us your constructive criticism" cause its easily bendable. it can be interpreted as "tell us why we suck" or "please put us down for your sake", on the lighter side, it can also mean "please help us become something better". try something that brings out positive more than anything else. why not say "we want you to have a happier experience here! how about you help us achieve that goal by giving us ideas on how to improve". As well: I HIGHLY recommend you change the name of "The Complaint box" its just negative and pushes people away. you are looking for ways to improve, not ways to see yourselves as bad. Honestly, everything with the section is WAY to negative and pessimistic.
I won't comment past that I don't really see this forum being necessary myself, if people have suggestions they've always posted them in the site discussion forum. That's cool with me, no need for the extra sub!
If i have complaints about something i usually just PM a staff member directly. I don't see any need for complaints to be posted publicly. Posting complaints publicly is only good for... Well, nothing really.
:/ at least try to see what im trying to say. All im doing is trying to help. Try being the word of the day.
I personally like the ideas you're trying to get across Skyraze. Just making things seem more positive than "Oh, criticize us in this section for complaints" does seem like an odd request. I'll take your advice on putting a more positive spin when requesting that someone let us know how we can improve the site. Perhaps instead of directing them here, just linking them the staff page and telling them that they can PM whoever they would like.