I believe your concerns are legitimate, however, I also am led to believe that the large presence of women voters on Sunday strengthens the likelihood of a secular Iraq that will be reflected in the new constitution. Also, polling has indicated that a majority of Iraqis prefers a secular government as opposed to one fashioned after Iran.
One thing we might agree on is that the election in and of itself demonstrates that US policy has always been strongly in favor of free elections and whatever takes place afterwards will represent the will of the Iraqi people. "No War For Oil" rings hollow.
I guess my trust in the results of polls done in Iraq is less than your own. Even if the polls are roughly reliable, the fact that Kurds, Baathist Sunnis et al. approach 40% of the total population might well boost the 'secular state' option well beyond anything the Shia have in mind. Additionally, the 'Sistani people' likely know his highness's ultimate aim is a theocratic state, with close ties to Iran -- with the self-interest caveat that this cannot be said at this time. The 'bottom line' for me is that I think the Shia in Iran and Iraq are indissolubly bonded and this will manifest itself -- later if not sooner.