Notice how I specifically said "10 years"- not 20 or 30.
9/11 changed a lot of things, including the US foreign policy in and long-term goals for the Middle East.
With the US & UK airforces, it would take less than a day of airstrikes to completely wipe out the Iranian airforce and navy. However, Iran does have much more powerful and longer range missiles than Saddam's forces. With their current tech, such missiles could hit anywhere in the Middle East, including Israel, and much of Europe as well. Fortunately, the US has been developing advanced missile interception systems, including anti-missile lasers.
Perhaps one of the most critical things would be to get the regular Iranian Army to defect and fight against the Revolutionary Guard. The Iranian campaign could played out much more like Libya than Iraq, but on a significantly larger scale.