Actually it was not necesity that made Germany innovate, it was Hitler waking up. From 1941 to 1943 he shut down almost all research and cut the funding for science drastically. Had he not been so stupid, he could have had Jet Fighters by 1943, and maybe even Nuclear Missles.
On the subject of Germany, i think their NA are a little underrated. The atlantic wall get decimate nearly any D-day, especially when combined with Fortress Europe, and personally, i think Panzerblitz is one of the bets NA’s. It allows hit and run attacks, so Germany doesn’t have to worry about the counter atack, since nothing will be left. If you can predict how many guys you will lose failry well, you can send just enough infantry in an assualt, send in a horde of tanks, and the run. Works well against Causcasses, since it disables the IC. Still, i think Britian has better NA’s (Radar, Joint Strike, Colonial Garrison, and Enigma can pretty much ruin any move the German’s make on Britian).