First, I repeat I have nothing against it, it will be more detailed and (we have to see) more realistic.
But I give one exemple: before you could build a division and deploy it, now you will have to build it, train it, and also build all the equipments needed. So more operations are needed, which is more complicated. It's fine by me, but its more management of production.
The tools for producing and deploying are a lot better now though (as are the tools for upgrading). I'd say that the overall unit management load (from production to warfare) will be less in HoI4 than HoI3 (assuming you didn't put production and theatre AI on, of course

), but that we'll actually have to think a bit more about what we were doing. So less actions (still plenty, just less than HoI3) but each action has more weight.
In terms of production as well - I'd expect that some lines wouldn't change that often, and that rather than adjusting sliders every day or two (something I won't miss much at all - I know they could be automated, but you could only choose it to 'max' one thing, where I usually wanted a couple of things maxed at once, so to get what I wanted required much fiddling) it'd be a case of every couple of weeks checking back in and increasing the factories used for Pz IIIs, or Spitfire Ibs, or what have you.
Oh, the famous 5 years plans !
Who said the famous quote "prediction is very difficult, especially if it's about the future" ? (Danish Physicist Niels Bohr).
As there so much things who can derail the bests plans, I always thought that it was the capacity to adapt to changing situations that was as much, if not more, important than the planning. In that way, capitalist/democratic systems were better in the field of adaptation/flexibility because of the free entrepreneurship and also, lets be fair, greed.
Aye, but the capacity to adapt is often due, in no small part, to good planning

. We'll still be able to adapt of course. Like others in this thread have mentioned, the rate of replacements (particularly for things like STR) felt too fast in HoI for the IC required. Now when we lose equipment, we'll have to replace it. Want to do a 1000-bomber raid to hammer German industry? By all means, but if you lose twenty per cent of your force, then you'll have to wait for them to be rebuilt again. If you haven't foreseen the losses, the factories won't be set up to handle the load and the strategic bombing campaign will be slowed down considerably.
Well you're right, but for some reason the majority of Hoi3 players never really mess with things like strategic bombing.
Aye, strategic bombing was plenty effective if you wanted it to be (and just a bit too easy playing as Germany, but then what isn't playing as Germany!), but there was so much micro involved. It wasn't too bad with the German campaign in a BoB-like scenario, as you were generally just focussed on that, but as a US or British player, balancing keeping an eye on your STR wings (which would fly themselves into oblivion even on the most passive settings without management) and escorts got very painful very quickly. Fortunately, the way it looks like its set up in HoI4 should make it a lot less painful to get things happening and maintained, so the air war will hopefully be a central part of the game, rather than an optional extra

.