@Luka George, I entirely share the basic spirit in your wish, but not the suggestions you made to achieve the goal of giving manpower the significance it really had.
Note that if I speak of manpower here, this is in the CoW1.0 sense of number of available soldiers, not in the CoW1.5 sense of available persons as workers OR soldiers.
Since all units in CoW are almost similarly powerful (sure, for example a tank unit in CoW is a bit more powerful than an infantry unit, but not so veeery much), we have to imagine a CoW infantry unit as containing clearly more men than a ordnance unit and an ordnance unit as containing more men than an armoured unit.
Because if you had artillery/AA/AT guns and even more so if you had tanks, you needed less men in a division for bringing the same relevance to the battlefield than if you had only rifles, hand grenades etc..
For example 100 tanks with 400 crew members and 600 accompanying support personnel had a way stronger impact on the battlefield than 1000 infantrymen.
On the other hand, infantry had lower costs in terms of economical resources. So for a country with a large population, but few resources and/or money, it made sense to primarily go for infantry and to build only few heavy weapons. The other way round, highly developed nations with a strong economy wouldn't let their precious men go to war by foot and without a lot of ordnance, tanks, planes, ships and so on.
The issue is that this is not reflected in CoW. Even if you have a lot of spare manpower in CoW1.0 (which you usually do), you still won't want to build a lot of militia, reg./mot./mech. infantry, because the economical costs of these four units are equal or even higher than those of other units with comparible usefulness.
To get this straight, food costs of the infantry units should be clearly reduced, while their manpower costs should be slighly increased. Details on this proposal I wrote in --> this post <--. That's a very simple change, which would aditionally have other positive effects.
Now after that change is done, then a historical map with differences between the nations as you (and I) desire them can be created. However for playability reasons, I wouldn't make a big difference in the amounts of manpower each country has at the start (as you suggested), but rather set the manpower production in relation to the population each province had at about 1932 - that would be awesome. For example province Leningrad on a historical map should produce 100 times more manpower than a tall province in the Sahara, a rural province in central England would produce more manpower than a province in the Romanian mountains and so on.
P.S.: About your suggestion to reduce or remove manpower upkeep costs of units, I wouldn't do this. Because maintaining a large army for a long time was - as @EZ Dolittle already said - a big effort. And thus it was a major strategic decision for nations when to do the mobilization / call to arms. Upkeep costs for economical resources and manpower are required for CoW players to face the same decision. And they make it important to have a lot of production sites, which is also an aspect of real-life WW2 times.
