regarding the Tiger tanks:
I know people always cite it's shitty reliability and the fact that it was a resource hog as the main reason that it shouldn't have been built. However I tend to think that while those weaknesses prevented the Tiger I and especially Tiger II from being the war winners many lay people mistakenly assume they could have been, the thought process behind them wasn't that flawed, when you consider that it more or less was an attempt to counteract Germany's primary weakness(aside from Hitler's batshit insanity) which was numbers. It could successfully achieve a highly favorable kill ratio, one which a T-34 clone or tons more Panzer V's could not. The problem is that no matter how effective the Tiger I or Tiger II were, they could never achieve the necessary kill ratio to counter Allied numbers, no matter how hard they tried.
Also, the argument that the germans could have taken the resources put into developing and building the Tigers into other weapons that could have done better also seem kind of a bit mistaken, as there is no known weapon that the germans had developed that could have changed the major facts of the war on the ground or more importantly, in the air.
I think that the real change that the germans should have made was not in what weapons they produced, but what political or strategic courses they should have taken, since that seems to have been the only thing that could have resulted in any kind of "win" for them.