I don't think we have to granulate "man power" in so much it would bog down game play. I understand the idea and context from where it is coming from, but, game play wise I'm still a bit confused how much you will have to have for that level of micromanagement to achieve just factory production different than having a higher level extrapolation without the micro.
How woudl this "bog down gameplay"? We're talking one or more decisions you'd activate with a single click of the mouse button. Were you expecting to have to read job applications and interview every single woman applying for work or duty or something?
these sorts of things can't really be added because once you've played a few times you will have figured out the 'options that work' rather than not knowing whether it wil work or not, this is one of the downfalls for games, is that you can keep trying until it works, for example, german 'total mobilization policy' can be activated once u go to war with poland, in reality there's more stuff to think about than just numbers... so yeah.
As you say yourself, there are lots of features like this already. Recruitment policy, research, etc. Sure, with experience you'll discover optimal strategies. This isn't an argument for not having these things in, rather I think the problem lies with options not having both pros and cons. The Black ICE mod, I feel, does a wonderful job at balancing decisions. For example, whenever you research industry techs, your country gains manpower more slowly, because people who would otherwise go to the front are being sent to work in factories. In vanilla HOI3, there's no reason to not take these techs as they
only boost your IC gain.
Personally, I feel decisions on whether to allow coloured, women, etc. into factories and the army, if done well, would work great gameplay-wise. Cons could be things like dissent from racists and chauvonists who want to keep the armies and factories reserved for white males.