epmaniac - 8:41 am on Apr 8, 2011 (gmt 0)
About 1) Yes, I am 301 redirecting possibly hundreds of thousands of link to homepage or relevant content page on main subdomain.
2) Yes subdomain has significant backlinks.
3) I recently only tried to eliminate thin and duplicate content and has successfully been able to do so also. Also pages indexed in google has gone down by significant amount around one million which I think is good.