Use of the weapons you suggested as possibilities would be even more inhumane in an urban setting.

Precisely. During the beginning of the war, weapons were used that were as accurate as modern technology allows. It was amazing to see what appeared to be a heavy bombardment in some areas of Baghdad while all around lights stayed on, and cars moved slowly down the roads nearby. Single buildings were destroyed, while leaving buildings next to them standing. Hopefully, this technology will be improved even further.

There were no refugees to speak of.

This source puts the noncombatant deaths of the major combat phase at a maximum of 4,300. While this is still a lot of people, it is extraordinary for an invasion of an entire nation against a defending army.

I think you will find that a lot of Iraqi civilian deaths since May 1 have been at the hands of the Islamists and insurgents.