I can't think of a movie that's realistic. The game Operation Flashpoint - Resistance is pretty good, however - sneak up successfully on an encampment and you have a target rich environment, but as soon as the shooting starts everyone goes to ground and then, Heaven help you.
In that game, I've laid out in the woods, gunfire all around me, not seeing or knowing where the fighting is, until some enemy soldier stumbles onto me and fills me full of holes. I've also had my sniper rifle on a covered rise, picking off dozens of enemy soldiers without having them so much as shoot back in my direction. All depends on how the dice fall.
Were Italian soldiers poor? Not the Foglore. Usually they performed abysmally, but when Rommel gave a team of them 88mm guns and trained them in Wehrmacht doctrine, they preformed incredibly well. The SS? Great kit, but the rank-and-file vets despised them - thought of them as gung-ho idiots and used them up accordingly. Again, it depended greatly on the particular leadership on the scene.
German soldiers weren't especially good. Their doctrine was. US tactical doctrine was terrible, and even worse in practice - Gwynne Dyer quoted a figure done by US Army researchers during WW II, that found that only 15%-25% of US soldiers in a firefight would so much as shoot their weapons, let alone engage the enemy. Of these, 9 out of ten shots were not even fired at any discernable targets - just cover fire, or to make noise. By contrast, virtually all German soldier would engage the enemy - because, instead of engaging the enemy directly like his US counterpart, a German squad-level NCO would go from man to man and direct their fire. Likewise Germans always aggressively patrolled their area, no matter how weak their manpower was; Americans rarely did. Again, an NCO issue and a matter of employed doctrine.
Remember the BoB scene, when the Captain faked a patrol at the end of the war, because he didn't want to lose any more men? Most US troops were not elite paratroopers, and were doing this sort of thing from the beginning. I know from personal experience - when my unit was stationed in Bosnia, there was a marked difference between the 10th Mountain's perimeter patrols and guard mount and that of the 1st Calavry artillery crews that replaced them. I literally was on a guard mount, when the COR and the whole mobile perimeter watch went to sleep in the West Gate hut; the COR placed me on guard mount, with my orders being to open the gate for vehicular traffic and to watch out for the SOG (who never bothered to inspect his mount).
A hundred soldiers, massacred without response? If a Serbian squad of seasoned troops came on through the West Gate that day with blood in their eyes, they could have wasted the entire south watch, then gone on to literally wreak havoc throughout Camp Eagle. I doubt I'd have even gotten a shot off.
That's the real military experience. Boring as Hell, you likely never will see combat, but if you do it'll be quick and utterly savage. You'll either hit them hard, or they'll do it to you. That's why, if you want to be "elite" like the Germans were in WW II, you go looking for the enemy, always. Most (sane) people aren't up to it.
What makes for an elite soldier? Killer instinct, good wits, bright but not too bright. A gangster's mentality - hit them first, with surprise, kill as many of them as quick as you can then bugger out. He has to be energetic, but able to sit quietly for hours waiting for a target. He has to take instructions, and be able to make decent decisions quickly. Your best bet are teenage athletes too stupid to know that they can die. Because, no matter how good they are (or think they are), that's what's going to happen to plenty of them as soon as the bullets fly. And of course, he has to have an abundance of plain dumb luck. The House has odds on this game, and - guess what? - you aren't the House.
Here, someone else can have this soapbox now.