Iraq did not have a proper command system in the first place, what little they had was infiltrated by US because Saddam used to be an US ally.
The gdp ratio was also much more in US favor, a country with comparable gdp ratio to Russia vs Ukraine for US would be Iran, not Iraq. Access to air defense is also worlds apart, with Ukraine having very large amounts of 1 generation behind Russian weapons whereas Iraq had mostly anti aircraft guns.
In short, the Iraq war can only be compared in scope to Russian conflicts in Chechnya or Georgia, in the terms that these were conflicts between Russia and heavily infiltrated barely independent states with no major equipment access.
