I always thought that part of the reason that elite units cost more manpower and militia units cost less manpower was to reflect the different manpower required. You can't throw a 60 year old man into an elite mountain unit, but you could put him in the volkssturm.
I don't like that resources and IC don't require manpower. I think the game should have a more complete treatment of resource gathering. Each province should have a limit for each resource that can be extracted efficiently by a maximum manpower (X0). When the amount of manpower X satisfies X<X0, resources equals X*Y, where each X manpower would each produce Y resources. For X>X0, . Above that limit then X manpower would produce Yexp(-C*(X-X0)) where C is for balance. So total resources produced would keep increasing with more manpower but would have diminishing returns. So if I really want to produce oil as Germany, I need to throw a lot of manpower at it. That said, I don't think that paradox will ever implement something like this. In any case, I would take railroads before this resource system.
I don't like that resources and IC don't require manpower. I think the game should have a more complete treatment of resource gathering. Each province should have a limit for each resource that can be extracted efficiently by a maximum manpower (X0). When the amount of manpower X satisfies X<X0, resources equals X*Y, where each X manpower would each produce Y resources. For X>X0, . Above that limit then X manpower would produce Yexp(-C*(X-X0)) where C is for balance. So total resources produced would keep increasing with more manpower but would have diminishing returns. So if I really want to produce oil as Germany, I need to throw a lot of manpower at it. That said, I don't think that paradox will ever implement something like this. In any case, I would take railroads before this resource system.