You can do whatever you like but I get better performance and less heat with shadows off and besides to me the shadows don't really look all that good.
Been testing a scenario I’ve been working on using map Asslt Large Hills QB-121 and the buildings on that map seem quite tough even against 88mm HE from a tiger. It could be just certain buildings or just the angle that might be causing the problem you are seeing.
In a game I was playing the guy carrying the shrek was killed and the second guy gave buddy aid and then picked up the shrek and eventually destroyed a tank so I would not say he is useless.
I've had units that would cancel movent orders to enter buildings for no apparent reason, would be nice if the game would give some feed back as to why.