But even if it's an algorithmic one, and since you submitted your reinclusion request and got your site reviewed by a google engineer, can't s/he contact you personally and tell you what you went wrong?
It's really a simple process:
Step 1. - Login to your site via ftp Step 2. - Delete all duplicate content Step 3. - Open your browser to your site Step 4. - If all navigation returns a 404 besides your "contact" page and "about" page you can get a pretty good idea of what the engineers are presented with - is it worth listing, no, not in most cases unless you have a very content rich contact/about page.