firelock

Hits will most certainly have an effect on crews, at least psychologically. The degree of that effect would be related to factors like what vehicle they are in, what hits them, training levels, preexisting fatigue, etc. Not sure how the game system reflects this but I assume it does. If someone thinks a 155mm shell going off 10 ft away from your APC would not effect you in any way, I beg to differ. Crew experience would be a major factor. In Black Sea, most crews, regardless of training, would have to be considered relatively inexperienced with actual combat. I agree with the post above that the normal response is often simply to seek cover. Sometimes just the distraction is enough to have a useful effect. 
 
Some of this discussion has jumped between WWII and modern combat. Big difference in an Abrams and a Sherman in terms of the effect non penetrating rounds would have. I personally feel most thin skinned vehicles like APCs would not stick around too long to find out what exactly is hitting them, but would rather seek to move and get out of the line of fire. The crew, knowing full well the lethality of modern weapons, would be affected at least in some manner, ranging from mild distraction to utter panic. Artillery in WWII was used on armor for just this reason. It has morale and other effects that go well past a simple kill. 
 
Love this game system, but one thing it does not model that well is the human element. It can tend to ignore the strong sense of self-preservation in humans. A certain percentage of soldiers have always shirked and even fail to fire their own weapons. It's a little too easy in this game to mount the Charge of the Light Brigade. I will level a building and then have a RPG gunner who was in that building pop up and and hit me from the debris. A fanatical member of Isis maybe, but a Russian conscript? Probably not. This is not a criticism of the game. Its done about as well as could be. Just could use a little tweeking in this regard. Anyone else notice the huge casualty lists that occur in a one hour game? Especially in infantry, I don't find them realistic. A unit that sees itself suffering 40% losses in 30 minutes will most likely become combat ineffective well before it can mount a final push to the objective. 
 
Real combat is often much more desultory than the game system tends to favor. Things are not decided in an hour. A lot more scouting and observation time is often needed to get men to risk their lives. A lot of scenarios tend to devolve into mad rushes for ground objectives, with little time to allow recon to get into position. The system sometimes forces a player to unrealistically disregard the human factor and just plow ahead. It models vehicle behavior pretty well, but the infantry is often pretty much forced to jog into battle or risk not getting into action at all. Of course I understand that realism had to be balanced with gameplay and enjoyability.