The problem with the manpower boost the fascists get is probably the increments for each "node" of the Focus Tree (3% and 4% if I'm not mistaken, I don't have the game). The problem could be eased by making so that the various Conscription Laws have an exponential cost and give 0.5%/1% more manpower if you take the fascist tree: this way lower mobilization would cost less (simulating the increased militarization of a fascist country) while the later ones have a really high cost (to show how the population became disillusioned by the military failures), so that, at the end of the day, you have the same 6%/7% increment but at a higher cost.
Of course there are problems with this: first, the economic, social and military penalties for going from 'Disarmed Nation' to 'Press gang every person with male genitalia and at least two limbs' are pretty much non existant; second it would require a certain fluidity of the system which, at this point, is as rigid as a steel pole a 0K tmperatures