Let's not fall into the "10,000 palis for 1 Israeli soldier" nonsense.
What Rumsfield, Abiziaid, and Casey did for several years in Iraq.
1. Run a catch and release program for Iranians.
2. Let the State dictate what should be military decisions.
3. Let politicians in Washington dictate the ROEs and even then they did not clarify them for the troops.
4. They didn't send enough troops and even then they put them all on giant FOBs far away from the Iraqi public.
5. They refused to deal with the Medhi Army and badr and chose to make deals with Sadr even after he declared war on the coalition rather then deal with him. They also let him pack the Iraqi police with Medhi Army militiamen
I could go on and on. But, suffice it to say in a few short weeks Petraeus has undone a great deal of what Abiziad, Casey, and Rummy did. They will all do down in history very badly.