Several rounds of cleaning everything that seemed wrong or at least not squeaky clean, major site redesign and several re-inc requests later, the site is at its lowest point in 10 years history. Yet not banned. I do get 5-10 daily Google referrals (3,000 to 5,000 before penalty) Long lack of Google traffic seem to have snowball effect - fewer visitors means fewer new links (also some older links naturally fall off) hence even lower ranks.
I think the key in restoring a site is in getting someone at Google look at the site again after you made changes. This is I think where I am not getting a break. I think I need an experienced re-inclusion request copywriter to make the message enticing enough for the Google temp to click his/her mouse , LOL.