I gotta admit, I'm not very hopeful about the Iraq Constitution. I'm not very confident in the ability of any group of humans to come up with a good constitution, and since many/most of the Iraqis developing the constitution have lived only in a dictatorship, the odds seem even more heavily stacked against success. Here are some things that should be in the Iraq Constitution (but I strongly suspect won't be). They are listed in roughly declining order of importance:
1) An Escape Clause: There should be some mechanism whereby directorates (provinces) that don't desire to stay as part of Iraq can leave. But there should be a time limit before which they can't leave (e.g. 15 years from the ratification of the constitution). And there should be TWO referenda, scheduled split by at least 3 years time, that require a two-thirds majority of votes in order to seceded. Further, if any part of the governate has a majority that's AGAINST secession, that part of the governate should be allowed to not secede (to stay as part of Iraq). Finally, all people born in what is now Iraq for the next 50 years forward should be allowed to maintain Iraqi citizenship, even if they are in governates that secede. In other words, suppose Quebec secedes from Canada...the people in Quebec would still be allowed to maintain their Canadian citizenship. It's very important to have an "escape clause," because it respects the idea that people can peaceably agree to go their separate ways.
2) Equal Sharing of Oil Wealth: The federal government of Iraq should NOT be allowed to keep the revenues from oil sales. Instead, the proceeds from oil sales should be split completely equally among all Iraqis. It's a mistake to allow the federal government of Iraq to keep the wealth from oil sales, to use for the "good of The People." Instead, all money should be split equally among The People, and the federal government of Iraq should be forced to tax The People to get its revenue. The Golden Rule (one of them, anyway) is: "He who has the gold makes the rules." The (black) gold should be given to The People. That will help them make the rules.
3) Term Limits for All Federal Officials: In the U.S., we have an 8-year term limit for Presidents, but no term limits for members of Congress or the Supreme Court. Iraq shouldn't make the mistake we've made. They should have term limits for everyone. The term limits could be quite long (12 or even 18 years). But they should be there.
4) A Constitutional Restriction Against Military Conscription: There should be a specific right in the Iraqi constitution against military conscription. Membership in the Iraqi military should always be voluntary.
5) Declining Government Spending: Currently, the federal government of Iraq spends somewhere more than 50 percent of Iraq's GDP. There should be a constitution limit, except in times of war declared specifically by the legislature, that reduces the amount that can be spent by the government, down to approximately 30 percent, over the next 20 years or so (and then caps the level at 30 percent thereafter). Once again, the reason is that "He who has the gold makes the rules." The federal government in Iraq is much too powerful.
6) Federal Government Payment for Those Displaced by Saddam Hussein: Saddam Hussein displaced many Kurds and others, and put new people on those lands. The federal government of Iraq should be committed under the Constitution to paying compensation for those land takings.
Those are 6 good items that really should be in the Constitution of Iraq. But I doubt they will be.