I was reading a failry mediocre military SF novel called "Jump Pay" that was done in fairly black and white terms. One side was good, the other bad.
Anyway, the good guys took reasonable care of their troops, treated them as humanely as possible, etc. The bad guys treated their legions of conscripts like shit, cared nothing for their welfare or even survival, etc.
An interesting situation came up when the accord troops attacked the hegemony on a planet they were using as a staging area for an assault on the accord. The planet was a bit on the warm side, in face it was so hot that it was at the extreme edge of "habitable". The accord forces were having a hell of a time dealing with the heat, even tho some of their vehicles had at least minimal environmental control, I.E. air conditioning on the heavy mobile artillery and such.
As they were attacking a heggie base during the day they noticed that none of the heggie forces were using their dreaded nova tanks. The accord troops weren't sure why, then someone had a thought and suggested that if the novas didn't have air conditooning it might be impossible for crews to function in them during the day on that planet no matter how much they were theatened.
Well, no one in the local accord forces knew if heggie novas had air condictioning, and apparently no one up the chain of command knew either. After taking the base and getting a ferw intact novas, it turned out that nope, the heggies didn't even put in a simple air conditioner for the crews comfort.
So, the hegemony is ran by a bunch of assholes who treat the troops like shit, hence their tanks have guns and armor but no airconditioners, hence they could not function under extreme temperatores, hence they couldn't use them in battle on this staging area planet and lost the battle, and the war.
The book was definitely no "Hammer's Slammers" novel, but at least I got one idea out of it: How something as minor as not putting an airconditioner, like the one in your car probably, into a tank could have a real effect on major military actions.
Next time I'm doing up some 'bad guys" and want to give them weaknesses to be exploited, I think there'll be a note in there about "No air conditoning on their tanks!"
BTW, the writer did a good job of not just saying it openly, but letting the characters figure it out, kind of like a good GM would not tell the PCs why the gennie tanks were not being used and let them take some good guesses.
I think this was a realistic and plausible example of a "bad guy weakness" that wans't overdone and that only came up in certain conditions, hence explains why the baddies never fixed it until it was too late. Good tidbit for a game design.