Contrary to what John Murtha, Dick Durbin, Kerry and the New York Times suggest, neither our soldiers nor their leaders want to harm innocent civilians (even when it appears that some of the civilians may not be too darn "innocent"). The military chiefs also don't want to leave a residue of bitterness against this country amongst the Iraqis that will last a century (although in the Arab world I suspect that may already be a lost cause, through failings on the part of that culture much moreso than our own).
I have read elsewhere, by people whom I respect, such as MG Bob Scales (USA Ret), that we are in danger of becoming an Army that is too busy to learn. I think on the enlisted side of the house, that is quite true (accelerated promotions, less NCOES requirements, less overall training, etc), but not on the senior officer side. The senior officers, in addition to their standard professional education, have ample time to mull things over even while in theater. The mission is as much execution as it is an ongoing experiment.
What does concern me on the officer side of the house is that while these leaders do have the time to mull over these things, reevaluate and rewrite doctrine, experiement, create, and learn, there seems to be a real disconnect between their ideas and the implementation of those ideas. The field-grade officer ranks lack any type of vetting process for promotion and the new ideas being thrown around often result in new staff officer positions - meaning that the demand for field grade officers remains high, which helps to ensure that promotion rates exceed the supply of great leaders, allowing the mediocre to advance with the top performers.
The result is that increasingly less able individuals are finding themselves with greater responsibilities. Many react to this by falling back on what they know and do well: logistics and recreating the garrison environment. And then you end up with what we have today: smart folks at high echelons coming up with sound doctrine and good ideas, but too little energy going into implementation of those ideas at or about BDE level because it might detract from the softball tournament or a disruption in the flow of Baskin Robbins ice cream to the chow hall. A little generalized, but more or less what I see happening.