[copeab]

A few points:

The undergunning of the Sherman was largely the result of the flawed doctrine of the US in having tank destroyers (like the M-10, M-36 and M-18) kill other tanks.

The Arado Ar 234 was the blitz bomber Hitler wanted the Me 262 to be, but had it showed up a few months earlire in it's role as recon plane, the Germans would have almost certainly spotted the D-Day invasion fleet assembling (at that time, the Germans really had no effective air recon over England).

The Me 262, with engine development problems, probably would not have entered service much sooner even without Hitler's meddling.

The US viewed solders as interchangable pieces and had a disgraceful method of replacing dead/wounded soldiers with new ones. The "we'll sacrifice four Shermans for one Panther" was just an extension of this.

The M-1 carbine (and especially M-2) could be viewed as an early version of the PDW concept -- a light, handy weapon for use by troops whose primary job isn't a rifleman.

Although the Germans get all the attention, the US successfully used guided glide bombs in the Pacific, mostly for destroying bridges in the CBI Theater.