#1 The Defence Secretary doesn't set policy. His position is just administrative. It's stupid to blame him for policies in Iraq since he's not responsible for those policies.
#2 Smart move by Bush. It defangs the main avenue of approach by the new Congress and makes their hearings on the point moot and not newsworthy.
I really don't expect the new person to be any different in substance. It'll be interesting to see whether the new guy, Gates, has a hard time getting his nomination through the Senate.
Iraq is still going to be a mess whether they stick Gates, Rumsfield or Jesus Christ in the job.