"As a gentleman with apparently 30 award view(?)" you seem very arrogant & childish to respond like that.
Anyway, a lot of people do not get that CM is a simulator, not a game. And no it's not an excuse, let me explain it.
What you see on screen isn't what's happening in the simulator. There's a lot more going on than what's visible or known to the player, for example a bunch of soft factors such as "Experience, Morale, Leadership, and other elements operate at the individual soldier level and collectively transform how units behave", these factors go way deeper than you think, you may have noticed that already.
About the LOS system, sometimes it bugs out, but I only had that happening 2-3 times IIRC. But it's not broken.
Soldiers can either be occupied, sending information trough (C2 Link), Tired, In shock, stressed out or the other soldier/tank sits still & is well camouflaged.
The LOS also isn't a simple ray cast as in RTS traditional games. A forest tile with trees on it for example has some randomness to it, I think it should be obvious why that is, if not; It's to simulate bushes/leaves/grass where a unit can hide in & look trough leaves. Spotting abilities & experience take a big role here. Take into account that most units are well camouflaged & are sitting still. It's thus very difficult to spot units in it. Buildings are even more tricky, as their layout is always unknown(Spoiler: it's not 1 room).
I hope this gives you some insight to what level CM actually simulates. And please, don't compare it to RTS games x).