There were many large problems with production for almost the entire course of the war. Things were compromised rarely for the sake of simple expediency, as that just doesn't appear to be in the German engineer's nature, but often by sheer force of circumstance and supply.
The fuel and crews thing is, of course, an ultimate arbiter of whatever happens on the battlefield. Particularly the crews, as a lack of manpower is kind of by definition an indicator of losing a war, it most likely negates any advantage of greater vehicle production. However in the other 'front' of the factories I'm becoming less and less convinced that a serious enough increase in Mark IV's could really be achieved (though if it were it conceivably could have assisted Germany in hanging onto their tenuous oil supply rather longer. The Tiger concept alone was an occupier of engineering time since 1936).

Is it possible that the greatest benefit of discarding Tiger, Panther, Tiger II would be the the more intangible freeing up of the design staff and often brilliant engineers who laboured over them? They could then concentrate more on the essential engineering core, things like improving engine life, transmissions, material/fuel efficiency etc? (perhaps even more advances in synthetic/alternative fuels, some of these chaps were truly world class).
For one example the men who worked on the Maus's efforts were well and truly wasted.
Beside this actual manpower I read recently that each design hour cost the reich 32.25RM each. A whole 100 of these precious hours were wasted on the 210mm Sturmpanzer Panther alone, a very minor project that also came to nothing. It seems that orders to cancel the more exotic projects only really become prevalant halfway through '44... rather late for useful engineers to get their teeth into more useful projects.

Cheers,
Adam.

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