The lack of troops retreating is a major problem for me.
Most battles in reality are won by breaking the opponents morale as much as killing his troops.
Here we must kill every member of a squad to ensure that later in the game they don't get their nerve back and ambush you.
SPOILER AHEAD
As an example, in the first campaign, there are a number of platoons of Syria infantry outside the enterance to the base.
After much pounding from my armoured vehicles they were decimated. However individual soldiers, with the rest of their squad lying around them as casualties, still pop up and fire off AK rounds. They therefore have to be wiped out before they can be bypassed.
I don't believe this is even remotely realistic even if they were fanactical insurgents instead of the milita/regular force I think they were.