I thought I was experiencing a bug, as when I mobilised for Poland I had insufficient manpower to complete mobilisation (first time ever!). I was at two year draft and I only had around 400 manpower when I needed much more. It was looking like I would not be in credit until after Barbarossa but the Fall Gelb manpower boost got me there. I don't know if it was intended but the manpower restrictions encourage higher draft levels and use of the diplomatic events for the declaration of war. This ends out working well (I'll be better prepared next time).
By way of report:
Nationalist Spain won in about 9 months.
Nationalist China lost to Japan in about 2 years (I gave them the highest level of support but it did not swing things).
France left half of the Maginot line unguarded after declaring war on me. Italy stayed out of the fight.
I often get British fleets sailing the Baltic. They outnumber my fleet and my bombers are weak against them. Ships in range of bombers should live in fear. Can you increase the effectiveness of bombers against ships?
And I too, had never realised you could select ship components. I thought they were added, once you researched them. This is a great feature but it was not well explained in vanilla!