This has already been discussed in great detail in "Does the US have a moral obligation to spread democracy"... In the end everyone gave up and stopped posting (no one's mind was changed)
Bad idea, and contrary to military intelligence analysis. General White and Shinseki were involuntarily retired because they dared to speak the truth about the troop requirements derived from standard analytical formulas.
Bad also because civilian casualties were (and are) uncounted and not considered before the invasion.
And because re-writing the Iraqi constitution to allow coalition-only ownership of Iraqi public property violates the Geneva convention.
I dont oppose destroying Saddam, but if you take it as an axiom that A=B B=C ==> A=C where A=going to war, B=Getting Saddam, and C=good, as I have heard argued by proponents of the war, you miss a hell of a lot of relevant information.