The defense fell apart because Thib went with a more offensive oriented line up.
Korver, Rose, Boozer are not outstanding defenders. With the 3 of them on the floor you have Deng, Rose and Korver to guard Bibby, Lebron and Wade. That means Rose is guarding Wade, not a great match up. Id rather have Brewer or Bogans on Wade and then Rose back on Bibby. The Bulls on offense need to be methodical and until Korver starts hitting with more consistency hes just to much of a liability with Lebron and Wade on the floor. You just cant even consider switching him to one of them.
Even if Rose can stay with Wade, the pick with Lebron just sets Rose up for an even worse match up. Bogans/Brewer both played Lebron adequately but asking Rose to is just pretty far fetched.
I think these are all problems that can be solved, Bulls were just missing shots, its going to happen. But the Bulls key is defense and they need to go back to what got them here.