I agree with most of our points horseback, including trimming and innacurate instruments (this later issue is not only a problem of US planes).
Regardless of ammount of armor or redundancy, if you look at the ammount of space occupied with critical systems on the P-47 you cannot deny that the chance of damaging something to some extend is greater than in other planes. But of course redundancy will make critical hits harder to achieve.
I took a look at the collision boxes on the P-47, both distributors are modelled and are slightly smaller than in reality, there's two magnetos placed behind the engine, while in reality the R-2800 had only one placed between the two distributors (unless I missed something while looking at the schematic).
The intercooler is missing, but the turbine and belly plumbing is there. Oil coolers are merged into a single smaller unit. (Cockpit armour plates and other internal parts are also modelled btw)
All in all I think the collision boxes itself are generous in favour of the P-47. The probability of actually hitting something inside the plane might be smaller than in reality.
The problem, if there's actually one (not saying there isn't, it's just that I dont fly the P-47, and when flying a bomber surviving a Jug attack long enough to cause damage with the gunners -I man the guns- is almost impossible) might indeed have to do with too big a chance to receive damage when a internal part is hit.
Pursuivant:
I dont have mayor problems with the engines on the Hs-129 on air to air combat, be it a human pilot or AI gunner, it's AAA that is obsessed with my engines
But yes, either the damage on the Hs-129 engines is exagerated (the cowling bottom half was armored after all), or is downplayed on other planes with engines of the same family (G-50/MC-200, IAR-80/81)