Within a few days my question along with several other topics I was watching were hopelessly buried.
I do remember recently that a few threads disappeared. I don't recall the specifics, and I am sure it wasn't you, but there were some troublemakers making personal attacks and generally being bad sports. I don't read every thread, but as you mentioned, I have seen plenty of rants, defect reports and general product unhappiness remain intact. Some of mine from days of yore are still alive. If a particular thread ever catches your eye as potentially being one that would get axed- hit me with the URL so that I can pay attention and find out what might be happening under the hood.
As far as the Community Site goes- I agree. It's actually something that I've become involved with. It will take another month or two, but good things are happening. It will house the new incarnation of Civil 3D Rocks amoungst other things.
You won't find much response from 'deskers on the DG for a few reasons. Many of us can't provide answers about why something is broken or works a certain way, and if we respond it makes it seem like we can. A few developers and QA people will pipe in when they have a good answer or would like to test a drawing further to track things down. Also, sometimes we know the answers but our confidentiality rules prevent us from telling, so any involvement would just make things worse.
This all sounds like a total pack of spin speak I am sure, but the fact is that Autodesk is a big company that makes products that are used worldwide. If you are expecting a nimble company with developers that are accessible to you and immediately responsive to your feedback, maybe Autodesk products aren't the answer. I really like working here and I believe in what I am doing, and I believe that every day my work helps move the art of civil engineering design forward.
I stand by what I said here:
http://www.theswamp.org/index.php?topic=23136.msg278927#msg278927 about how best to get involved in moving Civil 3D forward.
While I can't always tell you everything, and I am not going to call out any of my coworkers, I will tell you what I can and take your feedback to the right people when its warranted.