I quite like this idea. In fact I was thinking of something similar recently where all heavy assets get a time-delay of about fifteen minutes making any tank, APC, Trans and CAS support literally support forces when the going gets tough. Imagine this on Muttrah. Infantry forces spearheading under heavy fire making their way till about Mosque and West City setting defensive perimeters, spec ops taking out fixed assets such as mortars and even the AA units. Perhaps a mortar crew providing support from Docks, and then when it's absolutely necessary CAS is finally up and provides targeted air support upon request. Trans finally delivers much needed supplies. Etc.
*Dreams on...*
Anyway I like the idea.