One major difference with Yugoslavia is that it broke up under it's own steam, and there hadn't been an outside invasion to tear things to pieces. That meant that it was at least in principle possible for outsiders to work constructively to try to help things get better once the civil war had erupted.

There is no way in which those involved in the invasion and occupation can play that play that kind of role in Iraq.

I can envisage a situation in which the Iraq government invites Iran to send in help to restore order, and tells the Americans and their friends to get the hell out. What then?