Let’s keep this in perspective: these ISIS guys are 1/10th the size of the Iraqi army. If those idiots would simply turn and fight, this would be over today.
The problem with modern Arab army is that they turn and run at the first sound to gunfire.
There's more to it than just that. Few Sunnis in the Iraqi army are motivated to fight (Sunni) ISIS on behalf of the corrupt Shia government in Baghdad. And I'm guessing that fact would demoralize the Shia soldiers as well.
Imagine you're a Sunni officer, and you're in the field against ISIS. The platoon to your right is mainly Shia, and is commanded by a Shia officer. Would you trust that platoon to protect your flank?
I think we are all in serious trouble with this group. They have big aspirations, a lot of support including the Saudis, and are said to be more brutal than the chechens or AQ.
I wish you were correct.