britexpat said:

" Iran's influence in Iraq increased as sson as Sadam was ousted. the presence or non presence of US Forces is irrelivant. The fact is that the Shiite majority in Iraq will always lean towards friendship with Iran."

True but, because of the huge military existence in Iraq, Iran was not able to shape the country for its own goals. Governmental, economical and military institutions were controlled by the US. So after the retreat of these forces, Iranian influence will be much more effective and visible. Iraq does not only consists of Shiites. There is a big number of Sunnis too.

britexpat said:
" As far as "domination of the Persian Gulf" goes, this is also irrelivant. it is only the Saudis and Americans who are playing on this issue."

Saudis are not a match for Iranian military and naval power. It is the US presence in the Gulf that counterbalances Iran in the Persian Gulf. So if the US would leave the Persian Gulf, many issues will arise in that region. Iran + an Iranian controlled Iraq in the Persian Gulf without US presence seems like a nightmare for the Saudis.