Let's look at the difference between Iraq vs Iran and our case.
1. In our scenario, we are moving in when the US has already made mince meat of Iran and we have a failed state in our hands. VERSUS: IvsI where Iran was at the top of their military and financial gain against a lousy Iraqi military
2. Iraq faced a totally different enemy topography - mountains rising creating a natural border that was difficult to penetrate effective.
We are facing flat, arid, dry desert-like land with clear air superiority and a far more effective air force.
3. Our military is one of the most professional and battle-hardened military in this planet right now. Iraq was a joke of a military with ridiculous tactics
4. We are taking over a predominantly Sunni territory, while Iraq was attacking Shiite territories and persian populations.
5. There is no major oil in this region. This makes it less attractive for foreign intrigue by countries like the US and UK.
PS: Did I mention how effective PAF is going to be on flat, dry desert terrain with the wide range of ammunition they have?